Swapping the "type" causes portals to no longer work as intended. Chunks would refresh immediately and nothing else happens. No crashes or warnings as it appears that the portal is attempting to teleport to itself. It is weirdly an unintended and effective way of trapping a player in a single dimension without any server plugins or datapacks.
Another thing to mention here is that the Nether has the complete removal of colored fog and the addition of shiny stars, the overworld night sky that cannot be affected using time commands.