I believe this is correct. It's also been my experience that when the batteries get low, it purposefully does not start the bluetooth on power-up, presumably to save battery. I forget if this happens when it's amber or red.
Okay, I looked and found this in the manual:
View attachment 108713
So if you let the batteries get low (as I do as a matter of routine), the bluetooth will not turn on automatically the next time you use the headset.
There's also this:
View attachment 108714
So, I think what could happen here is if you don't manually turn the headset off when you're done flying, then get in your car and drive away, it might be trying to re-pair, can't, and so turns off the Bluetooth. The headset of course is supposed to turn itself off after a certain period of time with no activity, but I suppose depending on the exact timing of events this could still be a factor.
(I will say that the headset lasts a LOT longer than 2 hours when flashing red. A lot longer. I found this out back when I had the Bose X and it's the same for the A20. I was replacing batteries a lot more than necessary, now I wait until they are completely dead.)