Testing T72367
The bug is about floating elements in the summary field, which you can't properly test on new threads because the summary function in LQT has been broken for ages. You should be able to test it by editing an existing summary, though, and checking its connected thread (random example: Summary:Thread:MediaWiki talk:November/hr/studenoga & Thread:MediaWiki talk:November/hr/studenoga). (Edit: I see now that you authored the task, so presumably you know this already, but I'll let it stay nonetheless.)