The compartor does not give a redstone output when place against an inventory block like dropper or shulker box, it only gives a signal when the any block around it is changed/updated.
Similarly when the dropper etc. is emptied it will continue it give a redstone output unless it is given a block update. This affects shulker boxes, droppers, dispensers, chests, hoppers, minecart withe chest/hopper.
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bemoty
Thank you for your report!
However, this issue is a Duplicate of MC-122159.
If you have additional information, please add it to that report.
Please search before reporting, as it's likely that one exists already.
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