If you've reset the board to default settings.
Then try everything in the process I stated above, that should solve your problem.
Also try replacing the battery if you have not done so already, all of this should fix your problem, if not then it may be that the standard board dwell is slightly low for your mini and needs to be raised 1-2 ms, refer to your board manual.
Then try everything in the process I stated above, that should solve your problem.
Also try replacing the battery if you have not done so already, all of this should fix your problem, if not then it may be that the standard board dwell is slightly low for your mini and needs to be raised 1-2 ms, refer to your board manual.