BG3 .lsv-files (saves) corrupted upon extraction/packaging (v1.19.5)

[Pbtngrko]

Using the last version (v1.19.5) and running the latest PC Patch (v4.1.1.6072089, "Patch #28"), saves are flagged as corrupted even if you only unpack and repackage them without even changing anything, regardless of compression used; also, no compression seems to match up with what the game uses.

This results in a pop-up when loading the save, which does not go away or resolve itself by creating a new game, and anyone joining the game will see their game crash.