To confirm, your original screenshot (portion shown above) is now obsolete? What is the setting currently?
For your filter, the translation seems to be “Exclude folder”. What’s the logic behind the content, and is that ~$[.\\x7E[^ shown? Is it your input (if so, please explain the intent) or something Duplicati came up with?
What I see looks sort of like regular expression intent, but Exclude folder aims for wildcards. This post was similar confusion, but it also points to a regular expression tester which might help if you’re trying that style (however you’d then probably want to enter it in the GUI using the “Exclude regular expression” dropdown).
Filters gives some basic explanations, but not far enough to explain how the different GUI dropdowns work. Additionally, the plus and minus syntax is somewhat specialized, but correspond to –include and –exclude which you can see (and control directly) if you try backup (for testing) using the job’s Commandline screen.
I’m not sure why your snapshot doesn’t appear to be working or complaining (unless it’s still set to on), but if that can be solved it would be a more general solution to locked files than filtering them out as they occur.