When the last stack is removed from a seed pouch, the itemCount NBT tag is not cleared. This can prevent these seed pouches from being stored together with other empty pouches (in drawers from functional storage for example) or stacking (bigger stacks).

Minecraft 1.19.2
forge 43.2.21
quark 3.4-405
AutoRegLib 1.8.2-55

also tested with
functional storage 1.19.2-1.1.4
bigger stacks 1.19.2-3.8.1

log n/a