I get set on fire when I enter the nether.

(For some reason, the Affects Version/s doesn't let me select 0.12.1 even though it has been released for Amazon. I am actually using 0.12.1, not build 13.) Whenever I enter my portal, I start burning when I appear in the nether, even though there are no fire blocks around. Most of the time I stop burning when I go back to the overworld, but a couple of times it didn't stop even then.