Impure Copper becomes Pure Copper in a Unit Storage

Issue description

found accidentally while designing an early game copper smeltery

Reproduction steps

Steps to reproduce:

1. Make impure copper
2. Put it on a belt into a storage shed with "pure copper" as the filter item
3. Profit

Game version and build number

v0.75c (b455)

Operating system

Linux

update: after a restart it seems to not do that anymore, game version is still v0.7.5c (b455).

25-06-16_02-36-autosave.save, 25-06-16_15-15-autosave.save, tranny ran an island for 43 years.save, Save 2025-06-15, 22-54-16.save, tranny ran an island for 55 years.save, 25-06-16_02-06-autosave.save, 25-06-16_14-48-autosave-paused.save, 25-06-16_02-21-autosave.save, 25-06-16_02-51-autosave.save

25-06-15_19-41-34_4449.log

25-06-16_01-35-38_3958.log

25-06-16_14-32-25_1466.log

Files not imported: 25-06-16_02-36-autosave.save, 25-06-16_15-15-autosave.save, tranny ran an island for 43 years.save, Save 2025-06-15, 22-54-16.save, tranny ran an island for 55 years.save, 25-06-16_02-06-autosave.save, 25-06-16_14-48-autosave-paused.save, 25-06-16_02-21-autosave.save, 25-06-16_02-51-autosave.save

I don't really think that's the case. I would venture a bet that trucks delivered the pure copper there and the impure is just pilling up in that mini connector. If you find otherwise, please file a new bug with a save file that reproduces this, but it's unlikely.