The description below is a copy from https://plus.google.com/+AndreyKuznet...
It seems we have found a bug in webhooks functionality.
I've created a modifier and assigned it to few products. If I delete the modifier via Edit item interface, Clover sends us a webhook about modified item. But if I delete the modifier via Edit modifiers interface and all items with the modifier are loosing this modifier. In this situation Clover doesn't sent any webhook about items that have been affected by deleting of modifier. ?