Duplicate thread for information.
The Checksum Button for ramsav's will be disabled in future releases.
The game stores portions of the save file in the RAM, and stores the checksum block at the start of the game. During gameplay, certain sections of the save may be updated, but the checksums will not be updated until the game is saved. Ripping out save chunks does not fix the checksums either, so any updated block will be 'invalid'; again, it was valid until the game changed it, and the game will then reapply the checksum when saving the game.
No issue here.