I went for a flight today and while flying the drone back to my truck while walking behind it, the right stick forward suddenly had the drone was crawling along 2-3mph (full forward stick) then the right stick did nothing at all forwards or backwards , all other controls worked right stick left/right left stick everything worked. It was just right stick forward and backwards ?? I had to turn it sideways to fly forward, I didn't have any other problems the rest of the time ,anybody have an idea what could've caused it..