Why do my Excel writers suddenly skip the first 4 colums in the Excel sheet?

Are you using a template .xlsx file in the writer?

Does your data have an xlsx_col_id attribute?

Do the first four attributes you are writing maybe have missing or empty values?

The records are being added to an existing Excel file.

Interestingly, there are four new extra attributes in an attribute manager preceding the writer, but I have the Action set to Remove for those. I wonder if that can have anything to do with it.

There is no xlsx_col_id attribute.

After removing them in AttributeManager check to see if they get removed in the writer. If not, remove them manually.

I don't see them in the writers to begin with, is the odd thing.

Then try recreating your writer

Recreating indeed solves the problem, thanks! Only now have to do it for 10 different writers...

Is your writer attribute definition set to Automatic or Manual?

I always switched it briefly to automatic to get the right attributes and then switch it back to manual, to be able to edit them if necessary.