Well, recently, I've come to see that a couple times when I'm doing /home, I get glitched through the floor. Mostly, this hasn't been a problem, because I can just use /home fast when I'm falling, and then just take fall damage but don't lose items. This time, I had about 10 stacks of couple and like 3 stone pickaxes, and I did /home and didn't notice I glitched through and fell into the void because I had switched to a different page(usually takes about 10 seconds for me to tele because I don't have the best comp)
I don't really care that I lost these items, but I'm just warning you guys that if you go to your island, make sure you aren't falling into the void.

 

here's a tip with your cobble generator mine down where you water flows into and then if you fall you can get in the water and come back without dying.

 

Try making a 'spawn' platform that is around 3 blocks higher than your bedrock level.
This may solve the problem.
Make sure it's solid though.