I play on the PC.
Haven't had any problems so far, rarely a game crash.
Now suddenly I have the memory problem.

It can be reproduced and always happens now when you act. If you load an old game and do not trade, you can save, if you trade with an NPC, the error occurs, no matter which char and which game state.
So it is a bug.

I have enough space on the disk, I deleted the contents from the levelcache folder.
I used the repair program to repair the game.
All this does not help. From one save to the next it doesn't work anymore, as soon as you act in the game.

So can no longer continue playing, with any character.

Is there a solution that you know and can describe to me?

Thanks

1 no its not a bug
2 the fix is to not mod your game or if you do mod then keep those mods updated as patches come out