Power query editor has changed type errors with new source

Hi v-jiascu-msft,

I just tried this again, here were my steps:

1. Go to Data Source Settings and change source (note, the new source has the exact same fields and structure as previous source).

2. Go to Navigation and select desired Excel sheet

--What happens next is two steps are automatically added to my query. Promoted Headers1 and Changed Type1. I already do this in my query, so I delete these steps.

3. Delete extra Promoted Headers1 and Changed Type1 that were automatically added after Navigation. 

My Applied Steps now look like this:

Source

Navigation

Promoted Headers

Inserted Merged Column

Filtered Rows

Removed Columns

Renamed Columns

Changed Type

My steps look fine until the "Changed Type" step. When I look at the error, it says the 'Sales Order Number' of the table wasn't found, even though it exists in all the previous steps. My work around for this error is deleting the Changed Type step and redefining the data type for all my fields. 

Am I doing something wrong? Or do I have to re-cast my fields every time I update the source? Thank you so much, really appreciate the help.

Best,
Bonnie