Since the new version 3.1.1, I've saw a few bugs, one bug was that on the backup of the new world with the server, I somehow resetted to stage 0, although i've unlocked all of the achievements. luckly the wiki helped me out on solving that. Another Issue is that the wolf head name is changed, to item.primal.wolf_head_item.name, found this when trying to find out how the cauldron works and the recipes for it. This update also causes people to lag out when doing /tp on people, causing them to rubberband. I also found this in the server logs that saying "quark loaded a new chuck [x, y] in demension 0 (overworld) while populating chunk (x, y) causing cascading worldgen lag.
Expected Behaviour
I expect things not to be glitchy but from the changelog, you expected things to slip by, apparently there is some thing that did, and ATLauncher made things a bit complicated when changing and updating servers.
Possible Solution
Steps to Reproduce (for bugs)
/tp someone far away and watch them rubberband on their end using discord video stream or some other software.
For the wolf head, just look at the item on JEI.
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commented
5 years ago 
Bug Report
Since the new version 3.1.1, I've saw a few bugs, one bug was that on the backup of the new world with the server, I somehow resetted to stage 0, although i've unlocked all of the achievements. luckly the wiki helped me out on solving that. Another Issue is that the wolf head name is changed, to item.primal.wolf_head_item.name, found this when trying to find out how the cauldron works and the recipes for it. This update also causes people to lag out when doing /tp on people, causing them to rubberband. I also found this in the server logs that saying "quark loaded a new chuck [x, y] in demension 0 (overworld) while populating chunk (x, y) causing cascading worldgen lag.Expected Behaviour
I expect things not to be glitchy but from the changelog, you expected things to slip by, apparently there is some thing that did, and ATLauncher made things a bit complicated when changing and updating servers.
Possible Solution
Steps to Reproduce (for bugs)
/tp someone far away and watch them rubberband on their end using discord video stream or some other software. For the wolf head, just look at the item on JEI.
Logs
Client Information
World Information
Server Information