Copper Golem path finding is broken

During the sorting procedure, copper golem isn’t able to open chest that are one block higher than him, event though they are placed over solid blocks (if we have four double chest one over the other one, it reaches them, wait for a second and change chests, so it doesn't open also the lowest chest, which should be opened because on the same y-level of the golem). If there are blocks like stairs over chest, sometimes it doesn't open them.