so as the title says, THE NETHER PORTAL are broken
i have proof in the screenshots and i will explain what specifically happened

first things first i moved my portal to my desired location in my own mineshaft that you can see on screen, teleported back to nether which seems to location which is even same as before i tried to change the location of spawning with teleport back there.

then teleported back, but not in the same spot as i moved my portal to mineshaft but near my house on train station

I thought, it was like 1 block in nether = 8 in overworld but it seems that this rule doesn't apply to pocket edition.