like Ripster said, checking for rivets seems the next step, warped stabaliser is a good call too, for example my stabalisers on numpad have a natural curve in them, and if i remove the stabaliser and put it the other way around it curves in the wrong way
so you did remove the spacebar key and re-seat it right?
mine is a bit picky, once it's seated correctly it always works, if it's not seated correctly it dosent buckle at all, sometimes i have to re-seat it 7 or 8 times, then it starts working normally like all other keys and never fails, but it sounds like yours is just buckling just before it bottoms out, I seen this happen when rivets were missing near this this key but there was like 90% of the rivets missing in this case :pound: