Worlds filled with invisible lava. When I log into any world I do not burn but if there are any mobs they act as though they were spawned in lava.

Mobs first light on fire then slowly swim up, magma cubes swim up a lot faster then the rest and don't light on fire. Item entities do not burn.

I am not sure how to reproduce it as I don't know what is causing it, I know it does the same for both 1.8.3 and 1.8.7 but I have not tested it in other versions