This was an easy one....
I had a second, non BCM dongle connected to my computer.
Thanks for letting us know you figured this out Jose.
I initially assumed that the computer was using a second dongle but that one wasn't powered -- I have a 7-port hub with switches to flip devices on and off. The black on black contrast made the 2nd dongle practically invisible so I didn't see it at first and I assumed that that was the culprit when I finally did spy it.
Close, but no cigar.
It turns out that something on my laptop is causing the on-board BT radio to turn on at boot, even though I have it explicitly turned off via the Lenovo Wireless Radio Manager. I never saw this behavior before so I assume it's due to some recent update. Laptop is a Thinkpad T440.
Moral of the story is: Check your device manager entries before posting a plea for help on the forums!