My buddy has a realm we've been working on for a few months(he plays on Xbox and pc, I play on android). When the nether update dropped he reset the nether. Now every overworld portal just teleports you into the nether and doesn't generate a portal on the nether side. We've built new overworld portals in different locations, we've built new nether portals in different locations. Unless the coords line up exactly you don't arrive in a nether side portal. We've been teleported inside netherrack, above lava oceans, anywhere the overworld portal determines the nether coords we get sent to exactly. I vaguely recall something like this mentioned in Hermitcraft videos a while back, and I guess the nether reset is to blame somehow so apologies if this doesn't fit the definition of a bug.