I don't know exactly when it started, but I think after the 0.11.0d update. I'm on 0.11.0e now.
Saving the game lasts much longer the more actions you take after your last save. If I click a few times through different menus it takes only a few seconds sometimes even finshing nearly instantly, but if I play through a whole day (crafting, managing, dungeon running, etc.) it takes minutes. The last time it took me more than 30 minutes until I gave up and tried to push the program to the background to check if anything else might couse this. The games engine crashed but I couln't find any reason for such a delay.
It seems like when saving, the game goes through any action taken since the last save and gives up after a certain point. This is realy painfull and makes the game nearly unplayable and this definitely didn't happen with version 0.11.0c.
I'm on windows 11 with very high end system hardware. So this shouldn't have to do anything with my setup.