I do not specify it on the command line, so I believe it has its default value of 30D. But the source data does not change not that often, so it’s completely possible nothing happened between mid November and mid December.
Yes, I ran it on another backup that has a local hard drive as a target, and it worked just fine. Well, it complained about extras, but it appears these are benign and can be ignored
Yes, it slows them to a crawl, B2 is throttling individual uploads.
I can give a hand, yes, of course. That being said, I have never encountered an error in SQLite itself, but always in my own setup of the library, or the queries I run against it.
For the problem at hand, I have created an issue to get the name of the broken file even at default log level. Then I removed the broken file from the backend as it keeps popping up as an error, ran list-broken-files and purge-broken-files to, I hope, get to a fixed situation.