Extreme Lagg

Put the summary of the bug you're having here

What I expected to happen was the Nether portal in the Nether would explode and the portals would merge as they were the only two left

What actually happened was.... I was trying to merge portals, I made a contraption that would hopefully destroy the Nether portal (TNT) and I would be teleported to "the main world" and in the end I had to keep in the Nether for time to pass as the TNT would only explode as I ventured back seeing if it worked it just exploded in my face.

Steps to Reproduce:
1. Consistent game playing
2. Build Nether Portal
3. Then teleport between world (frequently) and searching between worlds.