Thank you for the quick reply.
That post was actually one of my links above under Troubleshooting, it was one of very few references to this exact issue I've been able to locate.
It's unfortunate no further follow ups have been made in 3 months. I'll leave a comment and see if the user replies whether they found a solution or not.
Holding 3 buttons did not work. The device returns through the standard sequence. Holding all three buttons through the <=====> progress bar results in either returning through the sequence or it only registers as a BTN1/BTN2 shut down. Abandoning the 3 buttons during the sequence simply enters DFU Start mode.