I have the same problem exsept others can't see my skin my friends wonder what i will be next
I'm currently running the latest version of Minecraft, which should be 1.9.2 (the debug says 1.9.2/vanilla)
I apologize for misinterpreting your previous comment, what you've said makes sense now that I've reread it.
I've managed to dig around both portals now, yet am still set on fire. Note that the first portal I created was in the overworld, and the second one of the pair within the Nether.
I cannot attach the video I've recorded as the file is too large, but I've dug around the portal and cannot find any lava that would represent a threat, yet the burning issue is persistent as of May 4, 2016.
Weird splits like that on your screen is usually a sign of bad GPU 🙂