Hello.
On my realm, the nether portals have been misteleporting on multiple occasions.
Important: For all these misbehaving portals, there is a corresponding over world portal, or a in nether netherportal at all times.
Incident 1: The misbehaving portal (overworld) sends me to the first in nether portal, thousands of blocks away from the corresponding portal in the nether. Upon re-entering the in nether portal, it sends me to the correct portal in the over world (near spawn), thousands of blocks. Away from the first portal.

Incident 2: Using the portal supposed to lead to the first portal mentioned above from the nether, this time it decides to throw me half a thousand blocks on the opposite side of spawn, and there was no portal present, and it did not generate one, leaving me stranded.

Incident 3: Entering a overworld portal, it sends me to a previously unknown nether portal.
In the middle of no where. Upon re-entering this nether portal, it again sends me to the same random portal, in the middle of nowhere. This leads into two hours of wandering the nether, and is very frustrating.

Incident 4: Using a portal supposed to lead to a corresponding over world portal, spits me out at the same location as Incident 2, but this time it generates a portal, but still leaving me stranded.

I'm afraid I can't give exact coordinates, as it is counted as a cheat for realms, and it is currently still achievement safe. (I'm sorry if the specific portals are confusing)
Thank you for your time