Blueparrot B350-XT headset won't power off when paired with my 2021 Macbook Pro M1

My Blueparrot B350-XT will not power off if it is paired with my Macbook Pro (2021 M1 Pro). As soon as it is paired, the flashing red light in the power button on the headset goes off, and holding it down does not power the headset off (or do anything at all). If I go to the bluetooth icon in the top right of the desktop, and click B350-XT (turning it from blue to grey) to disconnect it, the red blinking light goes back on and I can now power the headset off by holding the power button.

I have updated my firmware on the B350-XT from 3.33 to 3.40 (I had to use a Windows computer because for some strange reason the MacOS Blueparrot updater had a greyed out Update button even when I was at 3.33). I have also reset the headset by holding the up and down buttons until it goes to pairing mode. None of this has helped.

Blueparrot does not support this with MacOS, but it did work fine with my old mid 2016 Intel MacBook Pro.