I just did a forum search to see if anyone else is having this issue. Did you get it resolved in the end?
My Throtttle hat stops responding on the top three positions (so up, and both diagonals) if the throttle is set anything less than 75%. I can see it happening in the control panel, and in game this equates to not being able to use my thrusters unless I'm throttled up... not good for docking/undocking.
My stick is an X52 Pro, only a few months old.