Well, after no issue for a while, it happened again. I think I know why.
I use the "voice" feature on my iphone to write for me, in several apps, and I don't think it ends the bluetooth connection as "cleanly" as a voice call does... and the EQs get zero'd, and then do not return to my settings.
I haven't tried do thing on demand yet. I use the FB app "messenger" a lot, and press the little mic icon...