Note: This world is on a locally running vanilla snapshot server. No mods are used in this video.

https://youtu.be/UMb5qw4Ek_A
In 20w12a, my enderman farm is insanely laggy. Back in 20w11a, it didn't cause this crazy amount of lag. I don't know what's going on, but when I am at my enderman farm the server's console spams
Can't keep up! Is the server overloaded? Running 2008ms or 40 ticks behind
Can't keep up! Is the server overloaded? Running 2025ms or 40 ticks behind
Can't keep up! Is the server overloaded? Running 7828ms or 156 ticks behind
I have no idea what changed in 20w12a to cause this, but it's pretty intrusive.