Welcome to the forum @ShaneKorbel
CheckingErrorsForIssue1400 and FoundIssue1400Error test case, analysis, and proposal #3868 found steps to reproduce that and also “Detected non-empty blocksets with no associated blocks!”. The fix by @BlueBlock went in yesterday, so should be in Canary soon, then Experimental, and Beta, BUT issue had to do with the source files changing during the backup, and I don’t know which reports here that fits. Yours sounds different, and I’ll leave it up to the individual reporters here to decide if above fix helps any.
Fix ‘stop after current file’ #3836 and Fix pausing and stopping after upload #3712 are current efforts, but I’m not sure where they stand. Note you have the developer of the first named request talking to you now.