I separated a stack of 10 and it wont go back together. Its like they are suddenly different items. When i crafted bandages the same thing happened where just 1 wouldnt stack with the rest. This happens in both my inventory and inside chests. No, it wasnt food becoming stale its been arrows, bandages, bug parts, etc. Ive tried taking a partial stack and saying deposit all into a chest on the other partial stack, still doesnt work. Clicking and placing the partial stacks forcibly on each other also doesnt work they just swap spaces. Even depositing 1 at a time wont allow them to go into the same stack. It either starts a new stack or if the inventory is full is grayed out entirely indicating theres no room even though there are partial stacks of the item in the container.

Appears to be something new they added.  Smaller stacks.  You have to upgrade stacking size with the milk molars.  They made the food less effective so you’re having to carry more and then made it so it takes up more space.  As if inventory already wasn’t already a problem. All they are doing is making the game more frustrating.