When interfacing with other mods that read/use the contents of the storage chest/barrel, if the barrel or chest has stack upgrades, it seems that external interfaces can only read it as a single stack of items instead of the full size of the slot. Unsure if it happens with all stack upgrades, the ones I have been using are the netherite ones.

CyclopsMC/IntegratedCrafting#106

Beyond auto-crafting, this might also be related with the inability to transfer more than 64 items per tick when hooked up to integrated tunnels as well.

Well sophisticated storage definitely does expose true storage stack size otherwise stuff like vanilla hopper wouldn't be able to insert into the expanded stack sizes or even you wouldn't be able to use the expanded sizes in sophisticated guis. I can take a look at adding the slot less api if it's used by more than Cyclops stuff, but the stack size would need to be looked at on Integrated Crafting side or I will need exact steps to recreate and versions involved.

My mistake, I didn't mean to definitively say that that was the issue, that is just how it appeared from my perspective. It very well could be something else.

The crafting fails for anything above the normal stack size (>64).

Versions:
Integrated Crafting 1.20.1-1.1.7
Sophisticated Storage 1.20.1-0.10.25.804

A simple reproduction is creating a simple interface/crafting system with one interface that crafts any vanilla recipe, and a check that has a stack upgrade in it with more than 64 item in a single slot. Upon attempting to craft anything above a normal stack size, the crafting planner views it as only a single stack and won't let the craft proceed, despite having enough items in the chest.