I have not seen a recent post on this or a specific answer. Was flying last week and got this "Ultrasonic systems error, return home immediately" shortly after switching to W mode from P mode, about 5 minutes into flight with 50% battery remaining. I did bring craft home okay and landed without problems. IMU and compass all in range both before flight and again after landing and battery change. Flew twice more and in W mode without problems. All firmware UTD on craft, controller, gimbal and batteries. Should I be concerned? Thanks!