I went to exit my Nether base, expecting to reappear in my overworld base in my jungle tree house. Instead, I popped out of a newly created portal on the beach. I tried several times after destroying the duplicate portal. Sometimes it worked properly, sometimes it created a new portal, both in the overworld and in the nether. The two portals that I want to transfer between are the two portals that were originally connected when I first built the portal in the overworld.

This is a realm world. I have uploaded a video to YouTube of the bug: [https://youtu.be/DFVWnRb4nN0

]The video is 74.4MB, so I can't upload it here.