Well.. So this is the worst.. Hopefully this bug can get fixed before it is release similar to other bugs in 0.4 as you mentioned.
This is actually the only actual bug left. All the other issues are unimplemented functionality.
The thing with this is that you can't walk into interiors like you can in R2 -- the doors and walls are completely solid. The only interior where this is actually a problem is the VCPD, which doesn't have the door in front of it and the objects haven't been moved to world 0; everywhere else, you can just set a pickup and teleport players into interiors like now.
Why the change?
Why not? The server and client are so radically different from R2, we might as well change the default port to make the distinction stand out even more.