Identifying Broken Shifts

Just put this into the Advanced Editor in Power Query and investigate the steps one by one... This does what you want. How to extract the relevant shift id's from it? That's what I leave to you as an exercise 🙂

// Shifts
let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("pZBBCsQgDEWvIq4L/YlVa3ejxyi9/zVGKBRnkkUlu/DJ4yfvPD2DacW2cnLIR8AB+GVMKfboTglIyKFPH38tA5sd4dka0/DDUioqGzWW6bnm7t0ku6vs7pjHXhSKki0OSf7b0/LXq7Jab5E3J8lOea4Gz5J977kaPFeDZ8FOeK4Gz83gWbLvPTeD52bwLNgJz529vg==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Start Time" = _t, #"End Time" = _t, ShiftID = _t, EmpID = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Start Time", type datetime}, {"End Time", type datetime}, {"ShiftID", Int64.Type}, {"EmpID", type text}}),
    #"Sorted Rows" = Table.Sort(#"Changed Type",{{"EmpID", Order.Ascending}, {"Start Time", Order.Ascending}}),
    #"Added Index" = Table.AddIndexColumn(#"Sorted Rows", "Index", 0, 1, Int64.Type),
    #"Reordered Columns" = Table.ReorderColumns(#"Added Index",{"Index", "Start Time", "End Time", "ShiftID", "EmpID"}),
    #"Added Custom" = Table.AddColumn(#"Reordered Columns", "PrevShiftEndTime", 
        each 
        List.First(
            Table.SelectRows(
                #"Reordered Columns",
                (inner) => inner[Index] + 1 = [Index] and inner[EmpID] = [EmpID]
            )[End Time],
            null
        )
    ),
    #"Added Custom1" = Table.AddColumn(#"Added Custom", "Delta < 8 hrs",
        each [Start Time] - [PrevShiftEndTime] < #duration(0, 8, 0, 0)
    ),
    #"Added Custom2" = Table.AddColumn(#"Added Custom1", "Shift Broken? (1)",
        each if not ( [#"Delta < 8 hrs"] is null ) and [#"Delta < 8 hrs"] then "Y" else null
    ),
    #"Added Custom3" = Table.AddColumn(#"Added Custom2", "Shift Broken?", 
        each 
        let
            NextRowShiftBrokenStatus = List.First(
                Table.SelectRows(
                    #"Added Custom2",
                    (inner) => inner[Index] = [Index] + 1 and inner[EmpID] = [EmpID]
                )[#"Shift Broken? (1)"],
                null
            ),
            Output = 
                if ( NextRowShiftBrokenStatus = "Y" or [#"Shift Broken? (1)"] = "Y" )
                then "Y" else null
        in
            Output
    ),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom3",{"Index", "PrevShiftEndTime", "Delta < 8 hrs", "Shift Broken? (1)"})
in
    #"Removed Columns"