Enmity portal spawned in an inaccessible location

As per the subject line, was clearing Fields of Misery to spawn portals using GoD DH.

I am not sure what mob I killed (presumably a flying one) but the portal spawned here:

The minimap shows its location better, but I am unable to access the portal.

Converted to https://i.ibb.co/GV3gXtp/Bugged-Portal.png and embedded for you here: