Thank you Stefan, but is the mentioned feedback portal a different channel than the feedback option in Office, via which I already send the bug report, but without an answer from Microsoft?
Feedback should go to the same people, regardless of where you post it. The advantage of using the feedback portal is that other users can see your feedback and vote for it.
If you represent an organization (business, education), you may have more options to report bugs and suspected bugs, for example via the admin center at https://admin.cloud.microsoft/?#/servicehealth.
P.S. Microsoft usually doesn't reveal how they prioritize feedback (except that any issue which may lead to data loss gets high priority).