Windows Stacks of items in my chest are being set to 1

[ethanol54006]

I started a new co-op run with my friend, and around day 6 we first noticed this, where he had distinctly put 2 copper bars in the chest, but when i opened later, there was only 1. then on day 10, he opened the chest, and we noticed our couple hundred wood had been reduced down to 1.

 

[Nike Leon]

That’s terrifying… I’m a hoarder so having my resources disappear would be terrible!