Dear Thomas Fischer2,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
According to your description, my understanding is that you want to filter the data in the table, and part of the data in one column is not displayed as independent rows. I would like to know if my understanding is correct. Please feel free to correct me if my understanding is incorrect.
If I understand correctly, I notice that you have added groups. I found in my tests that the filter ignores the data when you collapse the groups
When I fold the filter it will look like the image below:
If my test results are not what you described, you are welcome to correct me at any time.
Sincerely,
Tin | Microsoft Community Moderator