I operate Mohist server(downstream of forge), When I was made ZombiePigman farm over the nether bedrock roof, Actually, I tried to fix this problem,
I tried Forge server instead of Mohist server, but my farm still does not work
I used kill command to eliminate any other mobs about disturb to my farm, but my farm still does not work
I checked about my server setting, but the setting is same to vanilla,
I was re-made my farm, but my farm still does not work
So, I was made same farm in vanilla server, This farm is work well,
So I reported this issue to Mohist server development team, but They recommended reported to Forge,
So I report about mob farm issue, I think that the monster spawn have some problems