I DONT KNOW WHAT HAPPEN . I JUST BUY IT YESTERDAY . FIRST TIME SWITCH ON IT ACTING CRAZY . ALREADY BALANCE IT MORE THAN 10 TIME . I USED TO HAVE GIMBAL BEFORE SO ITS NOT A BALANCING PROBLEM
I had the same issue on one of my gimbals from Aliexpress.
The reason was failure of one of the roll axis sensors. It was on SimpleBGC software and I have fixed it later in service.