Please make sure that your firmware is updated (2.7.1).
Also I recommend to perform test with Rescue mode described in the manual. This apply also for all stabilisations, it is important there is no drift and swashplate is not tilted.
Quote:
The easiest test for checking the rescue is to fly the helicopter in very normal way (your style). Then, immediatelly after the flight while rotor is not spinning anymore, you can activate the bailout/stabilisation. If you can see that swashplate is in the horizontal position and helicopter too, then it should work correctly anytime during the flight as well. This is very safe method for checking the operation.