Duping when using Deliver item to NPC in a quests plugin

[Reflect-good]

Type of bug

Exploit, Compatibility issue

/ess dump all output

https://essentialsx.net/dump.html?id=f6c57e1d011e40bbb21c0b81eb278bd7

Error log (if applicable)

https://paste.gg/p/anonymous/bfc6f2c1b59c4c0fa8bd48f391cc5a9b

Bug description

I have already reported this to the quest plugin dev, I see that its something to do with essentials, so im going to report it here aswell, when I try to give an item to my npc to deliver items for my quest plugin, the item dupes and gives me this error in console. Only reason why im reporting it here is because it has to do something with essentials.

Steps to reproduce

1. Give item to NPC
2. spam click
3. May happen during any quest stage
4. you'll see stacks start to turn into 512, 1028, etc, up until integer limit

Expected behaviour

The npc should just take the item without any errors, and give the next task.

Actual behaviour

Item dupes and gives error code in console.

Additional Information

none