@Andreas_Philipp1 I can find no reason in the Cloud metadata to suggest grouping of the metadata on our servers (and certainly not with the incorrect work titles), so this points to something client-related; as does the HWV313 and HWV 313 inconsistency in the part names of tracks 6 and 7, which comes directly from the Qobuz track titles.
As you probably know, performance grouping is performed on local library content and also, I believe (I need to check), streaming service content when there are no groups on the album coming from the Cloud.
Have you done any merges relating to the Concerti Grossi, even if you think them unimportant?
Perhaps you might try re-identifying (re-identify, not identify) the album to see if that fixes it?