Server spawning huge amounts of "crate_underwater_basic"

Hey Community,

Since Today I experience, that my server spwans huge amount of underwater crates and after 12hours uptime I had over 60k Entities of this type.
Some Ideas why this junk is spamming my server? Solved this for now with a simple function that kills such entities on spawn, but thats not the best solution :D

(My server is a Creative one, so This underwater boxes are not needed and removing them entirely from the server is not a problem)

Thanks for any help! <3

(21:55:39) | [TC] crate_underwater_advanced
(21:55:39) | [TC] crate_underwater_basic
(21:55:39) | [TC] knife.combat.entity
(21:55:39) | [TC] crate_underwater_basic
(21:55:39) | [TC] crate_underwater_basic
(21:55:39) | [TC] crate_underwater_basic
(21:55:39) | [TC] bow_hunting.entity
(21:55:39) | [TC] crate_underwater_basic
(21:55:41) | [TC] planner
(21:55:41) | [TC] crate_underwater_advanced
(21:55:41) | [TC] crate_underwater_basic
(21:55:41) | [TC] crate_underwater_basic
(21:55:41) | [TC] crate_underwater_basic
(21:55:41) | [TC] salvaged_cleaver.entity
(21:55:41) | [TC] crate_underwater_basic
(21:55:41) | [TC] wall
(21:55:41) | [TC] smallrechargablebattery.deployed
(21:55:42) | [TC] wall
(21:55:42) | [TC] crate_underwater_basic
(21:55:42) | [TC] pickaxe.entity
(21:55:42) | [TC] crate_underwater_basic
(21:55:42) | [TC] crate_underwater_basic
(21:55:43) | [TC] wall.half
(21:55:44) | [TC] wall.half
(21:55:44) | [TC] crate_underwater_basic
(21:55:44) | [TC] crate_underwater_basic
(21:55:44) | [TC] crate_underwater_basic
(21:55:44) | [TC] crate_underwater_basic
What plugins do you have installed on your server?
I wrote the most by my own. Can't list them all. 
Then can't really help you. Take a look at the plugins you have installed