You could try to search the forum for resetting dictionary, I remember a thread about emptying/deleting it because it kept suggesting passwords. Once located, reset the dictionary, maybe a bad entry keeps it from suggesting.

As for holding keys together I have no clue. Maybe you have a stuck key? If you double-tap the arrow, do you get a yellow notification that Fn is locked? If it works it might be a temporary relief.

Also, the lock never worked in browser - maybe it's in background and interfering? I'm basically just shooting in the dark at this point.