FLOOR ITEM LIMIT

On skyblock, Whenever I put items on the ground, they disapear. The item limit is always full. I also have checked all islands i have and everywhere ive built and cant find any items on the floor

What I expected to happen was...:
it to drop normally

What actually happened was...:
the item limit is full and will basically delete anything i throw 

Steps to Reproduce:
1. throw something out of the inventory
2. ...
3. ...

(im unsure if i should add, but i am currently on the desert island)