Normally unstackable items made stackable with a data component fail to stack on insertion

[LeraRiemann]

This happens when inserting items either via terminals or inventory hoppers. To reproduce, /give yourself any non-stackable item with the max stack size data component of 64, grab a full stack of it and try dumping it into the system. The items will be inserted into chests one-per-slot, ignoring this custom component as if it's not there :/

[LeraRiemann]

(the environment is 1.21.1 fabric, btw)