When the copper golem picks up a bundle from a copper chest and searches for a match in nearby chests, it does not recognize another bundle as a match and does not sort the original bundle into the chest. This happens regardless of the contents of the bundle, even if both bundles are empty. Both bundles are of course the same color as well.
Steps to reproduce:
Spawn in a copper golem and place down a normal wooden chest
Obtain two empty bundles of the same variety/color
Place one of the bundles in the normal wooden chest and the other bundle in the copper chest
Observe how the copper golem collects the bundle from the copper chest but does not put it in the wooden chest after searching it for a matching item
uhm, feels like a feature request