columnwidth argument in TableColumnProperties has no effect

[Jeff900]

I've been trying for a while to create a table in an ODT file and set the column width. But I can't get it to work following this example for creating tables: https://stackoverflow.com/questions/74655068/how-to-create-a-table-in-a-opendocumenttext-document-using-odfpy. In that example the columnwidth argument is used with "0.2in" as value. But in my document every column is the same size spread over the whole document width, no matter what value I use in that argument.

I also checked the content XML after I edited the generated document manually. I can't find any obvious differences between the values I try to use and the values in the content XML. The only difference I see is that the manual changes also result in a rel-column-width definition in the XML. Am I doing something wrong or missing something, or is this indeed not working properly?