Groupers for Structure add-on does not work

We want to group Structure (Version 6.0) by fix/affects Bundle according to you documentation https://denizoguz.atlassian.net/wiki/x/CABHBQ

This is an amazing new feature that we want to use extensively - but it simply does not work (see screenshot). Structure does not recognize the fix/affects bundle fields, we have to group by “text attribute”/fix in bundle and the result is then shown as seen on the screenshot.

We also recognized (maybe this is somehow related to our problem?) that the custom field “Bundle” is NOT available to be used in Jira, your documentation seems to be outdated: https://denizoguz.atlassian.net/wiki/x/H4C9E