Hi!
I've been having the same problem (where the keyboard goes crazy and "forgets" the assigned settings). Space bar is one of the problems, but the "a" for selection also disappears. The thing that really gets to me is that this seems totally random. For a while it had been working ok, I chose portuguese (that's my keyboard) for language and made sure that when I saved the settings in final cut that was the language I was using. But now it just went crazy again! It says I have the right keys set on the keyboard layout, but then it doesn't work while editing.
I'm just trashing the preferences as it has been suggested on some posts I've read online, but I'm not very hopeful...
It's really annoying not to be able change the keyboard settings with all this hassle...
Please post if you've found a (permanent) solution for this problem.
Thank you!