5 beeps

I have an APM 2.8 (Banggood or HK version) but supposed to be the same as 2.6.
After I arm the motors I occasionally get 5 quick beeps from the buzzer…not ESC’s. This usually happens once right after takeoff and that’s it. Today though I noticed that if I pick it up and move it, it starts giving me a series of 5 beeps until I set it back down…and keeps doing it when I lift off. It’s not very stable either. If I lightly tap on the FC or wiggle some wires it does it too.
Also starting at the same time, when I switch to Loiter, it takes off straight UP until I switch back to stabilize and land. It’s never done that before. Related ??
So I’m guessing that the 5 beeps are an alarm for something serious. But I can’t find any documentation about this.

Anybody ???

I remember having a similar problem when I connected a 3s battery to my fixed wing set up for 4s. I was just testing gimbal movement, but as soon as I started moving servos, I would get a beeping that I never heard before.

This is a complete shot in the dark, but that’s the only experience I’ve had that sounds similiar to the beeping you’re describing, and it sounds like you’re experiencing it under load?

Here’s a video of what it’s doing.