Sorry if this is old news but there seems to be something weird going on with nether portals.

I created a new one under a village i found and claimed today and it worked fine, only when i tried to exit the nether via the portal i came in through, instead of reappearing in the village i was in a cavern under the ocean more than 500 blocks south of the village.

Not sure if this is related, but draze and i have been having problems with our portals clashing as well, even though they're over 128 blocks distant from each other in the overworld.

they need to be over 1000 blocks apart for them not to clash

As Q said 1000 blocks apart not to crash and if they do i think they go to the first portal placed

Mine was placed first as far as I'm aware, but the netherside portal now sucks me over to draze's build.

And none of this explains why my village portal shot me under the sea!

To get the portals linked up the following should work:
build the portal in overworld first but do not light it up. Write down the coords. Take some other portal to the nether and go to the exact same coordiantes (divided by 8 ofc). Build a portal there, light it up but do not enter yet. Return to overworld and light up the portal there, then enter it

cant light portals in the nether anymore, the obsidian just "melts" :\

Don't light portals in the nether. If they come through into someones house then you will get into a fair bit of trouble over it

Yeah, and that kinda bothered me since your portal was there first Skip. only fair that it should go to yours.