I had the same issue: When I put keys back on keyboard, the key stayed pressed in. So I followed James Cocker’s advice. It did not work in the first place, because the little plastic hooks on the downside of the keys were bent. So I carefully bent them back (with iFixit Angled Tweezers) (such that the small scissor clips are able to fit into the key’s small plastic hooks) and it worked again. Phew…

After repair, I have still the same GPS issue (not precise and slow tracking) and now I cannot connect bluetooth devices anymore… Everything worked fine and I did not touch any contacts…

Why?