Appending Excel in Power Query Error

Hi Ibendlin, I'm the code is below:

let
Source = SharePoint.Files(SharePoint, [ApiVersion = 14]),
#"Filtered Rows" = Table.SelectRows(Source, each ([Folder Path] = "https://dialogue/grp/WG7393306/DashboardDatasets/CSGC Project Data/")),
#"Filtered Hidden Files1" = Table.SelectRows(#"Filtered Rows", each [Attributes]?[Hidden]? <> true),
#"Invoke Custom Function1" = Table.AddColumn(#"Filtered Hidden Files1", "Transform File (2)", each #"Transform File (2)"([Content])),
#"Renamed Columns1" = Table.RenameColumns(#"Invoke Custom Function1", {"Name", "Source.Name"}),
#"Removed Other Columns1" = Table.SelectColumns(#"Renamed Columns1",{"Source.Name", "Date created", "Transform File (2)"}),
#"Expanded Transform File" = Table.ExpandTableColumn(#"Removed Other Columns1", "Transform File (2)", {"project_nu", "region_id", "region", "sap_fund_code", "PROGRAM_ID", "prog_code", "prog_name", "prog_type", "cost_centre", "actprovid", "actproven", "orgprovid", "orgproven", "org_name", "legal_name", "business_number", "org_type", "org_category", "BANK_NAME_EN", "TRANSIT_NUMBER", "BANK_NUMBER", "ACCOUNT_NUMBER", "BRANCH_CIVIC_ADDRESS", "BANK_POSTAL_CODE", "mailing_city", "mailing_address", "mailing_postal", "act_city", "act_address_1", "act_address_2", "act_postal_code", "CFP_IDENTIFIER", "CFP_intake_start", "CFP_intake_end", "CSGC_intake_start", "CSGC_intake_end", "PROJECT_OFFICER_NAME", "Setup_INPROC", "Setup_REJECT", "Setup_WD", "Setup_CANC", "Setup_COMPL", "Asses_INPROC", "Asses_REJECT", "Asses_WD", "Asses_CANC", "Asses_COMPL", "RecAppr_INPROC", "RecAppr_REJECT", "RecAppr_WD", "RecAppr_APPR", "appl_source", "appl_date", "status_en", "ack_sent_date", "recom_date", "appr_date", "event_date", "project_st", "project_en", "CLOSE_OUT_DATE", "fund_req", "fund_appr", "fund_agree"}, {"project_nu", "region_id", "region", "sap_fund_code", "PROGRAM_ID", "prog_code", "prog_name", "prog_type", "cost_centre", "actprovid", "actproven", "orgprovid", "orgproven", "org_name", "legal_name", "business_number", "org_type", "org_category", "BANK_NAME_EN", "TRANSIT_NUMBER", "BANK_NUMBER", "ACCOUNT_NUMBER", "BRANCH_CIVIC_ADDRESS", "BANK_POSTAL_CODE", "mailing_city", "mailing_address", "mailing_postal", "act_city", "act_address_1", "act_address_2", "act_postal_code", "CFP_IDENTIFIER", "CFP_intake_start", "CFP_intake_end", "CSGC_intake_start", "CSGC_intake_end", "PROJECT_OFFICER_NAME", "Setup_INPROC", "Setup_REJECT", "Setup_WD", "Setup_CANC", "Setup_COMPL", "Asses_INPROC", "Asses_REJECT", "Asses_WD", "Asses_CANC", "Asses_COMPL", "RecAppr_INPROC", "RecAppr_REJECT", "RecAppr_WD", "RecAppr_APPR", "appl_source", "appl_date", "status_en", "ack_sent_date", "recom_date", "appr_date", "event_date", "project_st", "project_en", "CLOSE_OUT_DATE", "fund_req", "fund_appr", "fund_agree"}),
#"Removed Other Columns" = Table.SelectColumns(#"Expanded Transform File",{"Date created", "project_nu", "region_id", "region", "sap_fund_code", "PROGRAM_ID", "prog_code", "prog_name", "prog_type", "cost_centre", "actprovid", "actproven", "orgprovid", "orgproven", "org_name", "legal_name", "mailing_city", "mailing_address", "mailing_postal", "act_city", "act_address_1", "act_address_2", "act_postal_code", "CFP_IDENTIFIER", "CFP_intake_start", "CFP_intake_end", "CSGC_intake_start", "CSGC_intake_end", "PROJECT_OFFICER_NAME", "Setup_INPROC", "Setup_REJECT", "Setup_WD", "Setup_CANC", "Setup_COMPL", "Asses_INPROC", "Asses_REJECT", "Asses_WD", "Asses_CANC", "Asses_COMPL", "RecAppr_INPROC", "RecAppr_REJECT", "RecAppr_WD", "RecAppr_APPR", "appl_source", "appl_date", "status_en", "ack_sent_date", "recom_date", "appr_date", "event_date", "project_st", "project_en", "CLOSE_OUT_DATE", "fund_req", "fund_appr", "fund_agree"}),
#"Grouped Rows" = Table.Group(#"Expanded Transform File", {"project_nu"}, {{"MaxModDate", each Table.Max(_,"Date created")}}),
#"Expanded MaxModDate" = Table.ExpandRecordColumn(#"Grouped Rows", "MaxModDate", {"Source.Name", "Date created", "project_nu", "region_id", "region", "sap_fund_code", "PROGRAM_ID", "prog_code", "prog_name", "prog_type", "cost_centre", "actprovid", "actproven", "orgprovid", "orgproven", "org_name", "legal_name", "business_number", "org_type", "org_category", "BANK_NAME_EN", "TRANSIT_NUMBER", "BANK_NUMBER", "ACCOUNT_NUMBER", "BRANCH_CIVIC_ADDRESS", "BANK_POSTAL_CODE", "mailing_city", "mailing_address", "mailing_postal", "act_city", "act_address_1", "act_address_2", "act_postal_code", "CFP_IDENTIFIER", "CFP_intake_start", "CFP_intake_end", "CSGC_intake_start", "CSGC_intake_end", "PROJECT_OFFICER_NAME", "Setup_INPROC", "Setup_REJECT", "Setup_WD", "Setup_CANC", "Setup_COMPL", "Asses_INPROC", "Asses_REJECT", "Asses_WD", "Asses_CANC", "Asses_COMPL", "RecAppr_INPROC", "RecAppr_REJECT", "RecAppr_WD", "RecAppr_APPR", "appl_source", "appl_date", "status_en", "ack_sent_date", "recom_date", "appr_date", "event_date", "project_st", "project_en", "CLOSE_OUT_DATE", "fund_req", "fund_appr", "fund_agree"}, {"Source.Name", "Date created", "project_nu.1", "region_id", "region", "sap_fund_code", "PROGRAM_ID", "prog_code", "prog_name", "prog_type", "cost_centre", "actprovid", "actproven", "orgprovid", "orgproven", "org_name", "legal_name", "business_number", "org_type", "org_category", "BANK_NAME_EN", "TRANSIT_NUMBER", "BANK_NUMBER", "ACCOUNT_NUMBER", "BRANCH_CIVIC_ADDRESS", "BANK_POSTAL_CODE", "mailing_city", "mailing_address", "mailing_postal", "act_city", "act_address_1", "act_address_2", "act_postal_code", "CFP_IDENTIFIER", "CFP_intake_start", "CFP_intake_end", "CSGC_intake_start", "CSGC_intake_end", "PROJECT_OFFICER_NAME", "Setup_INPROC", "Setup_REJECT", "Setup_WD", "Setup_CANC", "Setup_COMPL", "Asses_INPROC", "Asses_REJECT", "Asses_WD", "Asses_CANC", "Asses_COMPL", "RecAppr_INPROC", "RecAppr_REJECT", "RecAppr_WD", "RecAppr_APPR", "appl_source", "appl_date", "status_en", "ack_sent_date", "recom_date", "appr_date", "event_date", "project_st", "project_en", "CLOSE_OUT_DATE", "fund_req", "fund_appr", "fund_agree"}),
#"Changed Type" = Table.TransformColumnTypes(#"Expanded MaxModDate",{{"region_id", Int64.Type}, {"region", type text}, {"PROGRAM_ID", Int64.Type}, {"prog_name", type text}, {"prog_type", type text}, {"cost_centre", Int64.Type}, {"actprovid", Int64.Type}, {"actproven", type text}, {"orgprovid", Int64.Type}, {"orgproven", type text}, {"Setup_INPROC", type date}, {"Setup_REJECT", type date}, {"Setup_WD", type date}, {"Setup_CANC", type date}, {"Setup_COMPL", type date}, {"Asses_INPROC", type date}, {"Asses_REJECT", type date}, {"Asses_WD", type date}, {"Asses_CANC", type date}, {"Asses_COMPL", type date}, {"RecAppr_INPROC", type date}, {"RecAppr_REJECT", type date}, {"RecAppr_WD", type date}, {"RecAppr_APPR", type date}, {"appl_source", type text}, {"status_en", type text}, {"appl_date", type date}, {"ack_sent_date", type date}, {"recom_date", type date}, {"appr_date", type date}, {"event_date", type date}, {"CLOSE_OUT_DATE", type date}, {"fund_req", Int64.Type}, {"fund_appr", Int64.Type}, {"fund_agree", Int64.Type}, {"project_nu", type text}, {"CFP_intake_start", type date}, {"CFP_intake_end", type date}, {"CSGC_intake_start", type date}, {"CSGC_intake_end", type date}, {"sap_fund_code", type text}}),
#"CSGC ID & Center" = Table.AddColumn(#"Changed Type", "CSGC ID & Center", each Text.From([PROGRAM_ID])

& " " &

Text.From([cost_centre])),
#"Intake Type" = Table.AddColumn(#"CSGC ID & Center", "Intake Type", each try

if Text.Length([CFP_IDENTIFIER]) > 4 then

Text.Start([CFP_IDENTIFIER], 3)

else null

otherwise

null),
#"AR Target Date" = Table.AddColumn(#"Intake Type", "Application Received Target Date", each if [CFP_intake_end] <> null and [CFP_intake_end] >= Date.FromText("2021-04-01") and [Intake Type] <> null then Date.AddDays([CFP_intake_end], 14) else
if [CFP_intake_end] <> null and [CFP_intake_end] < Date.FromText("2021-04-01") and [Intake Type] <> null then Date.AddDays([CFP_intake_end], 21) else

if [CSGC_intake_end] <> null and [CSGC_intake_end] >= Date.FromText("2021-04-01") then Date.AddDays([CSGC_intake_end], 14) and [Intake Type] <> null else
if [CSGC_intake_end] <> null and [CSGC_intake_end] < Date.FromText("2021-04-01") and [Intake Type] <> null then Date.AddDays([CSGC_intake_end], 21) else

null),
#"AR Fiscal Year" = Table.AddColumn(#"AR Target Date", "AR Fiscal Year", each if Date.Month([Application Received Target Date]) < 4
then
(Date.Year([Application Received Target Date])-1)
else
(Date.Year([Application Received Target Date]))),
#"PD Target Date" = Table.AddColumn(#"AR Fiscal Year", "Payment Date Target Date", each Date.AddDays([project_st], 14)),
#"PCO Target Date" = Table.AddColumn(#"PD Target Date", "Close Out Target Date", each try

if [PROGRAM_ID] = 324 then

Date.AddMonths([project_en], 4)

else

Date.AddMonths([project_en], 6)

otherwise null),
#"PCO Bin" = Table.AddColumn(#"PCO Target Date", "Close Out Bin", each try

if [Close Out Target Date] < [CLOSE_OUT_DATE] then 0 else 1

otherwise

0),
#"SS1 Bin" = Table.AddColumn(#"PCO Bin", "Service Standard 1 (Bin)", each try

if [ack_sent_date] = null then 0 else

if Duration.Days([ack_sent_date] - [Application Received Target Date]) <= 0 then 1 else 0

otherwise 0),
#"Assessment Days" = Table.AddColumn(#"SS1 Bin", "Days to Assessment", each try

Duration.Days([Asses_COMPL] - [appl_date])

otherwise null),
#"Recommendation Days" = Table.AddColumn(#"Assessment Days", "Days to Recommendation", each try

Duration.Days([recom_date] - [appl_date])

otherwise null),
#"Approval Days" = Table.AddColumn(#"Recommendation Days", "Days to Approval", each try

Duration.Days([appr_date] - [appl_date])

otherwise null),
#"Assessment Date" = Table.AddColumn(#"Approval Days", "Assessment Date", each try

if [Asses_COMPL] <> null then [Asses_COMPL] else
if [Asses_CANC] <> null then [Asses_CANC] else
if [Asses_WD] <> null then [Asses_WD] else
if [Asses_REJECT] <> null then [Asses_REJECT] else
null

otherwise

null),
#"Fund Code - CSGC - Cost Center" = Table.AddColumn(#"Assessment Date", "Fund Code - CSGC ID - Cost Center", each try

Text.Combine({Text.From([sap_fund_code]), Text.From([PROGRAM_ID]), Text.From([cost_centre])}, " ")

otherwise

null),
#"CSGC ID & Cost Center" = Table.AddColumn(#"Fund Code - CSGC - Cost Center", "CSGC ID & Cost Center", each Text.From([PROGRAM_ID]) & " " & Text.From([cost_centre])),
Funded = Table.AddColumn(#"CSGC ID & Cost Center", "Project Funded", each try

if [fund_agree] > 0 then "TRUE" else "FALSE"

otherwise "FALSE"),
#"Days to Acknowledge" = Table.AddColumn(Funded, "Days to Acknowledge", each try

Duration.Days([ack_sent_date] - [appl_date])

otherwise null),
#"Days to Setup" = Table.AddColumn(#"Days to Acknowledge", "Days to Setup", each try

Duration.Days([Setup_COMPL] - [appl_date])

otherwise null),
#"Measurement Date" = Table.AddColumn(#"Days to Setup", "Measurement Date", each if [CSGC_intake_end] = null then

if [CFP_intake_end] = null then [appl_date] else [CFP_intake_end]

else [CSGC_intake_end]),
#"New Fields Type" = Table.TransformColumnTypes(#"Measurement Date",{{"region_id", Int64.Type}, {"project_st", type date}})

in
#"New Fields Type"

The issue happens between the #"Expanded Transform file" and #"Removed Other Columns" and #"Grouped Rows"

Thanks,