A specific nether portal sets me on fire every time I enter it (overworld to nether transition). I checked the blocks around the nether portal for something that would set me on fire somehow, but there's nothing.
The same portal set me on fire when it linked to a known safe location as well as once I set up the portal in the proper spot in the nether.

Uncertain how to reproduce (except it happens every time in that specific portal)

Edit: added youtube video.
https://youtu.be/93AkGNWxXGg