This sounds like everything is working as it’s designed to. Transition maps are AFAIK just empty worlds that act as temporary holding spots for clients while you move to the next map, for seamless travel (they store the Playerstates and Playercontrollers). The main thread still loads the next world so the transition world will be blocked / won’t tick while that happens - it just exists.
If you don’t need seamless travel, you may want to look at my Loading Screen tutorial I posted a few weeks ago which uses a tiny bit of C++ (you can literally copy-paste) - and allows you to display ticking objects and/or movies & widgets on the screen in between map transitions. Long story short, you can’t tick a world while you load another one, unless you hack it all in with Level Streaming (which comes with it’s own problems). It does work on PS4 too.
Also, if you’re not doing networking / multiplayer you don’t need to use ServerTravel at all. OpenLevel is what you probably want.