I cannot replicate this as I have no idea as to what caused it, I was afk almost all night waking up intermittently to log back on because it kicked me for not doing anything, and one of those times I went to get food, i discovered a massive hole in my miner farm, it is just a bunch of ore gems on top of each other with hoppers and miners, etc, I did not see the items on the ground or in my inventory, so I used the button in the skyblock book to retrieve them, everything was doubled, then I realized my spawners were missing, so I did the same to retrieve them, I got 9 of them even though I should have only gotten 3.