I found out what was causing the save error. It arose when I changed a container trailer to a cargo trailer in a large crusher, if there were objects in the container. Then I went to bed and got a save error in the form of the inability to save the game and a permanent "save" banner, as well as the inability to manually save the game or interact with the objects of the world. Only loading by F6 helped.
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- After I removed all the items from the container, replacing it with a cargo trailer does not lead to errors.
There is also a funny mistake related to the replenishment of oxygen through the tank - the system writes that O2 is replenished, and then writes that H2O is also replenished :-) Even if there is almost no water in the balloon.