I am playing MCPE 1.1.4 on my Samsung Galaxy S4. I built an underground nether portal in my house. When I try to go to the nether it is working fine and it takes me to the nether but every time I try to go back and exit the nether it takes me to other places instead of my underground nether portal thus resulting to infinite stacks of obsidian and it is annoying because I now have 2 double chests full of it. I even tried doing what my friend told me to do which is to build a nether portal outside my house first then use it to go to the nether and die there then go back to that portal outside my house then activate it again but this time not go in there but instead use my underground nether portal then go back again to fix this bug but it did not work. He even told me to just destroy my underground portal and just use the portal outside my house but I don't want to because I put a lot of work and time on designing my underground portal. Now, I'm always having second thoughts on going to the nether because I'm frustrated on this nether portal bug.