As you know, nether are NOT supposed to catch on fire in Minecraft when hit with a Fire Aspect sword. Yet, I have seen that Piglins, Brutal Piglins and Hoglins always catch fire when hit by one.
Linked issues
Attachments
Comments 2
Duplicate of MC-172087.
Its possible that piglins can cause fire before you post enything search google first
Google response:
Both Fire Aspect and Flame are nullified on all Nether exclusive mobs other than Piglins and Hoglins due to fire and lava immunity. Normal skeletons and endermen are not immune even in the Nether.