It's a glitch for a reason. Meaning it doesn't happen EVERYTIME you fall into the lava. You could jump into the lava 13,598,158,158 times and never glitch. It's random and happens for no apparent reason at times.
womp.
Actually, I think some of the screen shots are pretty decisive, as well. If I could come back into the server, I'd be glad to test this 100 times over and over.