When the copper golem inserts an item into a double chest, it updates only the half (single chest) that corresponds to the slot where the item is placed. This means that a comparator placed behind or on the side of the specific half of the chest that received the item will detect the change, while a comparator behind the other half will not. As a result, comparators attached to different sides of the double chest can give different readings, because only one side is actually updated when the golem inserts an item, not the whole double chest.
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When the copper golem inserts an item into a double chest, it updates only the half (single chest) that corresponds to the slot where the item is placed. This means that a comparator placed behind or on the side of the specific half of the chest that received the item will detect the change, while a comparator behind the other half will not. As a result, comparators attached to different sides of the double chest can give different readings, because only one side is actually updated when the golem inserts an item, not the whole double chest.