I had this same problem with my ch pedals as well. I had to always keep firm pressure at the bottom of the pedal to prevent the parking brake releasing all the time. In order to fix the problem, I wound up recalibrating the pedals without fully letting off the “brake” axis, but acting like I did. In other words, I made the pc unaware of this extra travel, so once outside the calibrated range, the pc wouldn’t react to the pedals. I’m sure this is confusing, lemme know if you understand.