Import Samples\Graphing\Categorical Data.dat
Set column C and D as categorical.
Click the Mirror to New Book button to create a mirroring sheet.
Active the created book, highlight column A and B, then open Stack Columns dialog.
Check Include Other Columns checkbox, column range C:D is filled.
Click OK.
==> In the stack column result sheet, no categorical info of other columns in column A and B.
Fixed in Origin 2026b SR2.