Did you try the 2s lipo with the lvc turned off, just to see if the same problem occurred or not? That would give an idea if it was the esc or lipo that was playing up for sure. Though, you've now tired a different lipo again ( 3s? ) and you dont get any issues with the lvc turned on?
I'd suspect its the 2s lipo dropping its voltage under load- what leds do you get when it blinks, then check those against this:
clicky