The bug is when there are multiple nether portals within a certain area around each other then the first one place is the one everyone comes out to. This is not ideal.
1. Make a nether portal in one area
2. Then go out about 200 x and make another nether portal
3. The first one will be the one for the second one also.
Environment
Windows 10 and java is Version 8 111
Dupe of MC-530