Hello I am opening an issue here since the subject is quite relative towards common use of quark and industrial foregoing in some modpacks.

Pastebin Quark-r2.4-321: https://pastebin.com/dAdPY7ax (with E6 modpack).
Pastebin Quark-r2.4-322: https://pastebin.com/UPC2id4K (with no modpack).

How to replicate the crash?

• Place a dispenser
• Place a button on dispenser
• Place an Industrial Foregoing conveyor inside dispenser mod required Industrial foregoing and titanium-1.16.5-3.2.8.7-22
• Use button
• Server or client will crash afterwards.

Forge version: 1.16.5 - 36.2.22
Quark version tested: Quark-r2.4-321and Quark-r2.4-322
AutoRegLib version: 1.6-49
Conflict or rather I'd say incompatibility between Quark and industrial foregoing.
First Discovery of the crash: reported by user @circee within Enigmatica6 modpack
At first I assumed issue was within industrial foregoing,
After my mistake thinking it would be one mod, a new discovery has appeared. which was that quark and industrial foregoing isn't compatible with each other
compatibility issue with industrial foregoing.
After few testing, I've removed all mods and kept

• Industrial Foregoing Version: 1.16.5-3.2.14.7-16
• Titanium Version: 1.16.5-3.2.8.7-22
• AutoRegLib-1.6-49
• Quark version: Quark-r2.4-321 then tested with Quark-r2.4-322 to see if issue persist within latest version as evidentially it does.

The only mod that's having incompatibility issue with industrial foregoing within E6(Enigmatica6 modpack) is Quark.
I hope compatibility issue to be resolved between quark and industrial forgoing.

Thank you.

After I've looked through with the mod itself, I've added the industrial foregoing conveyor to the blacklist Quick Fix for this issue
As well as this fix isn't perfect, it's just a fix where instead of dispenser placing the conveyor on the ground, it just throw it out, it worked single player and multiplayer without any crashes.