FOLLOW UP. RTD made it right and refunded me for the batteries. Understandably, they wanted photos, which I was not able to provide, but when the facts came out they refunded my entire purchase immediately. Good customer service goes a long way!
Per my (limited) experience the cells even if used in pairs, the voltages are not the same.
Unfortunately, I did not take photos. Only one cell vented (and that quite dramatically). The other was in tact, although the wrapper sustained damage from the fire. This is my first experience with a thermal run away, but I've always been the cautious sort. I ordered the batteries from RTD electronics and I inspected them prior to charging. No bulging, discoloration. The wrappers were complete. The initial voltage was 3.74 in one cell and 3.76 in the other. I obtained the NiteCore charger from Amazon. After the fire, I discarded both AW cells along with the charger. The charred remains of the guilty cell appeared almost inside out, splayed open like a hot dog left in the microwave too long. The electrical wiring in the walls is from 2002. I don't think the charger was fake, but the cells are a question mark. I've never used that site before.
I had almost similar issue, just I was nearby and reacted quickly and removed battery and thrown it away. What happened, that due to positive pin of charger being a bit longer than it be, and battery wrapper at top end being slightly damaged, when charger heated up, that long positive pin of charger shorted battery positive and negative terminals together. I heard a hissing sound, then see rapid smoke and fire from melting parts, but I've managed to quickly snap out battery from charger, so when short removed, explosion will avoided. I have photos of aftermath somewhere, can post, if anyone interested.
A related PSA...
I went to home depot and bought a few 6x6 ceramic floor tiles (a good ceramic dinner plate would do as well).
They cost about $3 each.
My chargers now sit on a ceramic tile as an additional precaution to limit any overheating or fire damage. Even if a charger goes up, the tile isn't going to catch and neither is the surface under the tile.