Rebound key gets unbound evertime Borderlands 3 start up (Steam)

Hello!
I’m playing BL3 on Steam and I’m using a mouse where I can rebind different keys.
For me one of them are the melee button/key and because I live in Sweden I use the letter ‘Ö’ for my melee key.
Problem is that everytime I close down the game and start it up again, that key gets unbound and I have to rebind it again