Invisible lava/fire from unknown source.

I managed to capture video of this event: https://1drv.ms/v/s!Ajqi2b64hBbUeH2-37pUExfRAcI

Only while holding a map in the offhand, I kept catching fire in one small area of these stairs, as if I were stepping in lava or fire that does not appear to exist otherwise. I do not know if this happens on other consoles/versions.