The bug
The average ticks per second in the latest pre-release is lower than usual. Old worlds as well as new worlds are affected. This was not an issue in 1.13-pre4.
This can be reproduced by using /debug
or lighting TNT and observing the delay for it to explode. Eating food also takes a while.
Linked issues
is duplicated by 4
Attachments
Comments 23

Happens to me too.
It seems like the further away you are the longer it takes to explode.

Generating chunks has always been an intensive process. It takes more time for the server to process more events with chunk generation.
I'm getting about 10-15 TPS on a world that has nothing going on. I'm pretty sure this is a bug, an a huge bug as well.
Despite what Matthew is claiming, i have noticed quite poor performance with pre5 as apposed to any of the other pre's and thats noticeable with only a few people online and when you get to 20 odd users, the screaming of lag is quite real. And with majority of users on my server all ready having a base and nether and the end being quite explored for the size of the map we have, its certainly nothing to do with new chunk generation.
@Matthew Hunter - I was using debug mode. Either way, your post comparing the two pre-releases is exactly the problem. Nothing is lagging, the TPS is just lower.
Seeing the same thing here. No lag on client side. Server runs at very low tick rate. Eating takes a long time. Mobs move slowly and jittery. None of the usual suspects seem to be at play in this world (no redstone or other mechanical contraptions). The lag started to occur shortly after switching from 1.13-pre4 to 1.13-pre5.
Also experiencing this. Thought it was weird when I saw pufferfish jolting forward. Checked out other mobs, same thing. Ran /debug, and now running 9-10 TPS, when I was hitting 19+ before (server is nearing completion, so no other players on atm).
Nothing has changed on my end, except upgrading to pre-5. Client side, everything seems fine except for eating food, and seeing mobs move slowly.
Also, restarted the server to clear up any issues that may have caused. Was at 9 TPS the moment I logged on.
This is again in 18w33a.
and 1.13.1-pre1
This is happening because your server is running at a slower tickrate.