Zombie Piglins Spawn in hoards when entering or exiting a nether portal after using a nether portal gold farm.

What I expected to happen was...:
To enter and exit the nether with no hoards of zombie piglins.

What actually happened was...:
When I entered the nether there were about 20 to 30 zombie piglins in my nether base. Then, when I decided to leave the nether that same amount spawned out of my overworld portal.

Steps to Reproduce:
1. Create a trident kill nether portal gold farm. (link to Video)https://www.youtube.com/watch?v=-uWbgCP6E5c
2. AFK at farm 
3. Enter/exit a nether portal