What voltage were you using?
I'm betting it's the circuitry or the head/coil that heated and not the battery. Do you know for sure what part of the mod got hot?
Many mods actually have wattage limits, not amp limits. It's amps @ X.X volts. (and volts x amps = watts). So it's possible it would be at the top of the wattage limit and then overheated if you continued to use it and maybe thermal trip. IDK for sure though, it would have to be tested to find out. If you're concerned, I don't blame you for using a different PV. This is just some "other possibility" guessing on my part.