So, I've built the latest version of Colormatic and installed multiconnect.
Tried to connect to minemen server using 1.8 minecraft protocol and has crash
Removing colormatic mod and/or connecting to 1.18.1 servers doesn't cause this issue
Log is below
latest.log

P.S. I am not sure which mod is causing this issue, but I've made a bug report in colormatic repository too
kvverti/colormatic#80

Found another problem which seems to be related to SmartHUD mod.
DeflatedPickle/SmartHUDReheated#6

Same as #293 I think