Copper golems only retrieve items from copper chests with stairs above after interaction

A copper chest which has a transparent block (in this case stairs) can be opened by the player but not by a copper golem, except after the player has interacted with the chest or periodically when it’s left to idle for several minutes.

Once it has finished sorting an item type, it will then move onto the next, but it is only able to sort 16 of those before stopping

See attached video (sorry for low quality, file size was too large before)