As of today. QS for enchanted book can be broken.
We noticed that after attempting to purchase an enchanted book the player is then able to break the chest. This ability overrides Towny, Grief Prevention, Region protections, and is only stopped by a Lockette sign.
It does give you the message that the shop has been removed, and it throws no errors in console. This only applies to Enchanted Book Quick shops.
Please post your server versions, plugins, etc.
I tried on Spigot 1.12, with latest version of QuickShop, and it works just fine with enchanted books.
You're talking about an "ability" that overrides protection plugins... is it a custom enchantment?
We are actually thinking its a lockette issue at the moment. Unfortunately we had a really busy weekend and didnt have time to take tje server down to test.