I do not have a crash report to this issue since it didn't crash my game it's a minor issue but i suppose it could be of use for the team to fix.

Steps to reproduce
It dosen't have a step other than the lag starts on the render distance
May or may not work that way, as far as i know every time i enter the area where my butterfly leviathan is, entities start moving slowly

Description of issue:
Mainly what appears to be server lag, entities moving slowly and ocassionally moving faster after a "lag spike" it is not frame rate, chest takes a little while to open when the butterfly leviathan is near, The lag dissappears once the leviathan has gone off the render distance, same thing happens with wild butterfly leviathans.

Extra information
These are the mods i've been using for the most part along WyrmRoost

If you'd like more information contact me at [email protected], thank you for your time Modders!

This issue appears mostly actually in vanilla. One of the forge devs, and I quote "Screamed at Fry during a live stream to fucking fix it"
(Fry is a mojang dev, Fry was watching the stream). Though ill look into it to 👍