it’s your settings file/unrelated to cloud
a potential quick dirty fix is you can just delete the options.txt or keybinds.txt in the folder path linked earlier
keep in mind the issue might appear again if it’s windows defender or AV or onedrive doing stuff
in your
C:\Users\*user name*\Documents\My Games\Grim Dawn\Settings
white list the entire documents/grim dawn folder in your anti virus and windows defender
if the folder isn’t in that specific location it means Onedrive hijacked it and you need to unlink and and disable onedrive
also whitelist/make manual exclusion for your entire grim dawn game install folder (not just the exe)
sometimes a simple use of repair tool in game install folder can also fix it, or verify game files or exit steam and launch it with admin rights then launch grim dawn and change settings
if you have particular sensitive AntiVirus like Avast or bitdefender you might need to take additional actions like disable ransomware protection for the folder or disable deep-scan/activer shields etc