I was with my minecart over a lava sea, up 5 blocks, from the sea level and i had a lag spike for the amount of lava on the screen, suddenly i start burning and i died for suffocating inside a wall.
Tried this twice and always happens.
I hope you understand this even if my english is not very well..
Thanks, keep up the good work!
I was on this map :
It's the Super Hostile map Sea of Flame II...i was trying to reach the GIANT PIG STATUE with the Minecart from the Monument Hall.