Yes, tex, I did that. I managed to raise the post a tiny bit, and that didn't work. I then raised it even higher, to where it was above flush (if that makes sense). I screwed it into the USB adapter and tried it, first in the computer. No lights on the end tip (though the USB charger glowed red, as it always had). Then I slotted the USB adapter into the wall charger and put it in three different outlets. No light on the end tip, though both the USB adapter and charger were glowing their usual colors. When I removed the battery from either the USB port or the outlets, the battery flashed blue three times, which is also what it's been doing for the past few days. There is no charge left.
I unscrewed the battery and the post was back down where it was before - i.e., below the lip/rim of the battery. So obviously it made contact in order to be pushed back down.
I levered the post back up, put it back on the USB adapter, and tried to twist it on more tightly this time, and the adapter case cracked.

I can't get the ruined adapter case off the batttery; will have to resort to pliers.
We now have two functional batteries out of four for the both of us. One is on the wall, charging normally, and I'm vaping on the other one but I'm now petrified that when I go to charge it, it also will display the same symptoms.
I just ran online and ordered four new batteries from a completely different supplier (mt vapor) but they won't be here until the weekend. I still haven't gotten a response from the original supplier, though I've written twice. Bit annoyed about that.
I am ready to switch entirely if this is normal. I am a geek and don't mind tinkering, but I cannot deal with this.