As I know, the past or the last update 0.16.2 the nether portal loads the nether as your screen wobbles or you have like the nausea effect as you go near the portal then you will be teleported to the nether.

But in the recently release version 1.0.0, if you will go to the Nether Portal... The screen appears to show the "Loading World" screen rather than the screen wobbles for a certain amount of time and then you will be teleported to the nether.

This was a feature back in 0.16.2, but this was removed or disappeared from the update 1.0.0