one elses. My nether portal TP me to some calmed portal. when I go back through it I'm 500 blocks away from my base.
Which server is this on? You can try breaking the portal and going trough again. Other than that it's a minecraft mechanic we can't change. You can try building one in the Nether at the same overworld coordinates as your other portal / 8 THis should guarantee they are linked
Had problems like that when I started but monkeybug34 tipped me of 2 use the Curse Launcher instead and it disappeard all together.
At the time the server started 2 act up monkeybug34 and Ovraline also was online. It first crashed and then afterwards was totally bonkers. They stopped playing but I stayed on for a while longer but it didnt go away.