I'm experiencing the same problem on my Galaxy S5. I built a portal to the Nether near my base. I entered the portal and hung out in the nether for a bit. When I decided to go back to the Overworld, I was spawned in a random location that I've never been, definitely not where I came from. I tried going back to the Nether, ended up in the same spot in the Nether I had been before, but when I go back to the Overworld I always end up back in that random location. This is extremely gamebreaking knowing I can never go back to my base already having put 20 hours into it now.
Illona Rose
I'm experiencing the same problem on my Galaxy S5. I built a portal to the Nether near my base. I entered the portal and hung out in the nether for a bit. When I decided to go back to the Overworld, I was spawned in a random location that I've never been, definitely not where I came from. I tried going back to the Nether, ended up in the same spot in the Nether I had been before, but when I go back to the Overworld I always end up back in that random location. This is extremely gamebreaking knowing I can never go back to my base already having put 20 hours into it now.