The overheating issue is in the driver itself, not the flashlight. The driver cannot get rid of the burnt off heat quick enough which causes the 7135 chips to overheat & initiate thermal throttling which drops the regulated amperage. I’m quite surprised that you don’t have the issue, more so because the forward voltage of the XHP-70 is lower than that of the MT-G2 which should worsen the overheating effect.
It might be your batteries that have more voltage sag than full blown high drain cells, but… I’m still kind of doubting if this is the case with your Soshines. So, not really sure why you’re not seeing the issue.
Anyway, I’m glad you’re ok. You can do some more reading about this issue here.