Copper golems on the south side line (east and west lengthways) seem to gather at one spot after picking an item from the chest (also most do not drop items into the last chest). It sort of resets when you quit the world and open it again but the same thing happens after a while (start to end of video)
Environment
Item sorter, 1 copper chest & 9 chests arranged as shown in video, has weeping vines for entities to ignore collision boxes
Please provide a copy of the world where you are experiencing this issue.