Well, I can report that my entire fleet of Provaris have been raised from the dead--although I hesitate to do so, because it's for an embassingly silly reason.
I cleaned the contacts, fully charged the
batteries--and nothing. Out of ideas, I observed that all the
devices with the exception of the Radius were set up in a 18490 mode, so I removed the extension cap from the Mini and tried a 18350--and it sprang to life. Ditto with the others and 18650s.
The Radius? I'd already tried both the 18650 flat-tops I have, but I tried again anyway. No dice, but I tried one last time: it lives.
So, of the small army of Li-Ions I had on hand, all proved functional but all four of the 18650s. Frankly, I hadn't metered them; i just trusted
thr blinking LEDs on my Nitecore.