When I first entered the Nether, the Nether Portal was in place, then I died and spawned at home in the overworld, when I got back to the Nether, I was teleported to where the portal was, and where it should be, but it wasn't, I had just been teleported to the Nether with no way back other than dying, when I built it back, it worked.
Another bug related to the same Nether Portal is that when I built a Nether Portal up on the bedrock level (y=128), and tried to go there by entering the Nether Portal in the overworld I was going to the old one (the one that bugged and disappeared), so then I broke the old one and tried again, and then the old bug happened again, I entered the Nether Portal in the overworld and I was teleported to the place where the old and original Nether Portal was, but there was not any portal, when I enter the portal on the bedrock level it sends me to the normal portal overworld.
This was not a problem for me that had cheats on, but imagine what a game breaker it would be for someone that is on hardcore, I assume it would be a bug that happened because of the Nether Update, because I have never experienced that in a stable Minecraft version before.
I hope it gets fixed, thank you.