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

23 hours ago, diesieben07 said:

Post logs.

Okay, but The logs maybe looks like corrupted partially, because We use Korean,

  

2021-05-07-1.log

On 5/8/2021 at 5:49 PM, diesieben07 said:

Please post the debug.log.

 

I tried to found debug.log, but I can't found that, would you tell me about the location of the debug.log?

It's in the logs folder. It's named debug.log.

Also, do not post a log of a non-Forge instance. We can not control what coremods/other hacks downstream projects might have. So if you're using them you have to get support through them.

If this is reproducable on JUST Forge. Then post the correct log, and include your world so that we can try and reproduce ourselves.