Brightness and BGM, and maybe some others, are not saved:
when I quit then come back to the game, I must set them again
("Brightness":"0,16667" and "BgmVolume":"0,4" come back to 0,2 and 1)

EDIT: Making the file "setting.save" read-only (in "\LocalLow\JoyBrick Inc\Panzer Knights") did nothing
Unsynch Galaxy cloud did nothing.