Hi firstly i want to apologize if this isnt anything to do with loliasm but the reason i put it here is because its the only mod i can see mentioned in the logs so I'm not sure if its just informational or bug related. when i play with my son in LAN whoever isnt the host if they die they crash with this error and a bunch of network related logs and they cannot rejoin.
latest.log again im sorry if your mod is unrelated

I had a look and while the crash isn't loliasm's fault, the problem could be quite hard to properly diagnose. Can you try to remove mods slowly and see when you stop crashing?

Some mods don't properly take into consideration of LAN mode, I recommend launching a dedicated server for you and your son to join. It doesn't take more resources than a normal LAN environment.

i see, thank you for taking the time to look into it anyway, you're a gem. i had an inkling its something to do with the recent mojang username migration thing. people using email addresses that are super long are getting passed as usernames in game or something when some mods send packet data and its causing an error. again thank for looking at this. ill close this :)

Do give an update if you do find the cause, we will try to spend some time on this too.

Hi, just wanted to let you know I eventually found out what it was. not sure what exactly what was happening but the mod called "Carian style" was the culprit. I went through all my mods and added them one by one until it crashed and its all fine now I've gotten rid of it.

Thanks! I'll try get in touch with the author or propose a fix over to UniversalTweaks.