realms spawning rates differ from single-player

Put the summary of the bug you're having here

What I expected to happen was...:
at 10 chunks set to render distance the gold farm i painstakingly built on my realm and single-player world should run the same, with the same amount of pigmen spawning when it is just me on the realm, no other players online. here is the design i used designed by ilmango https://www.youtube.com/watch?v=l9oteFEj770

What actually happened was...:
on my realm one small group of pigmen spawned, and once they died about a minute later another small group spawned, not the constant stream of pigmen so fast it fills up your xp bar at 117000 xp/h

Steps to Reproduce:
1. build this farm https://www.youtube.com/watch?v=l9oteFEj770
2. build it on a realm and a singleplayer world
3. hit a pigmen with a snowball in survival

4. stand on the trapdoor

5.watch amount of pigmen spawning