Are you using non-english letters? Like ü, ä å ö? Can be the culprit! I found myself flying at some 1500 mph when replying a mission and I had been at 200 000 ft MSL! Guess I´ll have to use US KBD!
I have remapped a lot of keys, ie I have "cykling VC views" on KP 5 and "go to pilotseat" on KP 3. The difference is obvious (to me at least), I have them mapped to my X 52 pro hat 2 up and down and it makes my life easy!