I cannot load any save games after Patch 5 when I have uninstalled all mods. I uninstalled, because I suspected my mods to cause a different bug.
The game warns me that loading the save without the mods might make the game unstable, but offers me to load anyway. If I choose “Yes” nothing happens. “No” does nothing either. This is true for all saves I used a mod with.
So basically, Larian managed to break their own game once more. Congrats. I'm actually impressed.