Fix Issue 6347: default constraints not applying to other categories

[matteius]

Fix issue with default constraints not applying to other categories + tests.

The issue

Fixes #6347

The checklist

• [X] Associated issue
• [X] A news fragment in the news/ directory to describe this fix with the extension .bugfix.rst, .feature.rst, .behavior.rst, .doc.rst. .vendor.rst. or .trivial.rst (this will appear in the release changelog). Use semantic line breaks and name the file after the issue number or the PR #.