Failed to save CODE 423

Hello, my game that has been running with no issues randomly stopped being able to save after todays update. The game comes up with the error code 423 (full image below), and will not save even if done as "save as". I tried going to manage worlds and saving there, it seemed like the save was successful, then when I open the game again there was no save and it goes back to a way older version.

I have never had custom content or mods downloaded and I have tried repairing the game multiple times.

Any help is appreciated since its basically unplayable at the moment.