When I played mc 1.16.5 with my friend, i crashed when i got back from flying
and i kept on crashing when i decided to enter our house
i asked one copy of the world and tested in singal mode,
i tried to remove optifine ,and i crashed again
i tried to load only optifine and quark ,crashed again
i tried to remove quark and i entered the house successfully,no more crashes
i recreated one same setting world ,with quark and without quark
the first time with quark ,crashed, the later without quark ,safe
the only things in the house(the house is a natural building),they're just chests of quark,hope u guys can help me!
2021-07-01-11.log

Is this a vanilla server?

Oh, it's definitely not vanilla if you have quark chests.

java.lang.ClassNotFoundException: me.pieking1215.invmove.compat.QuarkCompatibility

This strikes me as suspect in the log. What mod is this?

oh....first,this is not a vanilla server,i just played with my friend,haha~not a real big server,p2p,
second i suspect this mod is Project:War Dance,this was the only mod which changed the combat mode.
link:https://github.com/Jackiecrazy/WarDance

but i need to say.....my friend an me didn't meet the crash and the error of Failed to synchronize registry data, closing connection until we developed certain level of the game,the interference factors are too more...first i was not a vanilla,and i used about 110 mods（but over 30mod were performance improving mods,haha）,which contained botania,slashblade,
my friend and i wanna keep quark still, 'cause quark chests contained all of our items.....and our caves cant work without quark

by the way,my device: 16g 3200mhz rtx 2060 R7 4800H

Hello! Quark's moved to 1.18 now-- unfortunately, this means that (unless your bug is critical and/or game-breaking), we're closing support for issues filed for versions prior to it (e.g. Quark on 1.16).

If your issue still occurs on 1.18, or if your issue happens to be rather critical (e.g. consistently crashing the game with no other mods present), please leave another note or open a new issue. Thanks for your cooperation!