I updated from 6.1.2.0 and any time I save a game it will crash mid save. After reverting the update saving worked just fine.
Here is a link to a log file. https://tinyurl.com/vbz3sed

That is highly unusual... I didn't change anything about loading saves or migration scripts or anything. I don't understand why... something about fluid boxes?

Could you try mining up any placed recyclers, then saving, then updating, and then trying to load again? If that also doesn't work, then it must be something in my script. If it DOES work, then that might signify something weird about Factorio's fluidbox logic in this specific setup.

Keep backups on every step, just in case. Worse comes to worse, I may need the actual save file itself.