Have been having quite a few crashes with quark in a modpack I've recently put together. The current issue is related to sophisticated backpacks but had almost the exact same issue with the newest Aether mod and a few other mods in the pack when I disabled them one by one. The game launches completely fine without quark and its additions so I am quite certain the issue lies there. Paste of issue below:

https://pastebin.com/6R4fErYE

Already explained in the pinned issue, optifine is incompatible and there's nothing we can do.