I'm experiencing the same problem. A week ago, I didn't have this problem. However, due to a recent update - I noticed that when pull the X55 stick backwards, not only the elevator moves but maybe the rudder and the aileron controls as well. I noticed that when I pulled back on the stick, the aircraft pitches up and rolls to the right. If I push the stick, the aircraft pitches down and rolls to the left. This happened on the F-15 and the Su-27, and yes - I flew them with PFM before last week.
Its an issue with my stick, because I tried Falcon BMS right after and the axes were fine.
Does this mean I need to rebind everything again, even though I already binded my keys to the new PFM controls?