I went to my enderman xp farm, which i was also at yesterday and it was working just fine. it's the checkerboard and water style, with the 3 netherrack fire boxes design. maybe 2 enderman spawned in properly then a pilagger captain appeared in the fire.  On my way back to the return portal there was an enderman on my glass bridge and there was another pillager patrol on the main island. as far as i know none of this should happen.