Sparsebundle file vs. dated Time Machine backup files

Yes, on the one hand the backup seems to complete (TM preferences show a new most recent backup time), but I'm still getting the "Backup Not Completed" message for the backup to the Drobo.

Thank you very much for your help and for the clarification on the dated APFS snapshot folders.

I have checked and am now able to go into Time Machine and restore a sample file that was saved on a June 12 TM backup, which was only done to the Drobo, and a file from the July 3 backup that was only done to the 2 TB USB-attached drive.

Thank you very much for the clarification and for all your helpful comments.

I did not read your original post on doing verifications. I have now done a verification, keeping the preferences window open, and I got the following message:

Note: I tried to paste in a screen image ... which said "Backup verification succeeded. The backup on 'Drobo B810n' has been verified."

I have also been in touch with Drobo customer support and some time after the post I did yesterday, I got an e-mail from them saying:

"Apologies about the late response. We are following on this case, we detected a minor file system corruption from the last log files. Can you send a new diagnostic file."

I sent the diagnostic file a few minutes ago and haven't gotten an answer yet, but it will probably take them a while to analyze the diagnostic file. Maybe the corruption will be gone now that the TM verification came out good.

Of course. I will post the result when I hear back from Drobo support,