Thanks for the suggestion, I’ll give it a try. I’m pretty sure I tried it before to no effect, but will message had actually progressed (or been covered up) by Unexpected number of remote volumes marked as deleted. now so hopefully a rebuild will do the trick this time.
Out of curiosity, did you also is 7z at some point in the job history? Hopefully not as that would mean the issue isn’t (just) 7z related.
Edit: Unfortunately it didn’t work. I think I may have somehow resolved the issue (perhaps as you did) but then ran into the ““Unexpected number of remote volumes marked as deleted” error” errors. 