I’ve been using the following setup for my project, which is a game made up of various “chapters” which need transitioning between.
Each chapter is made up of a persistent level with art/audio/design pieces in separate level files under the persistent level.
To move between levels, I’m trying to create a “loading room” the player goes to while the next level loads. I found the transition map configuration in project settings and started using that but am not getting much success!
My GameMode class is marked as seamless and has the following code to change level:
WorldContextObject->GetWorld()->SeamlessTravel(LevelName);
However, in editor, when the final level loads, the sub-levels don’t seem to have loaded at all, with only the persistent level visible. When stopping during PIE, I go back to the first scene I was in, but now even outside of “play-mode”, any sub-levels are gone and trying to either save or play again crashes the editor.
If I play standalone, the level loads up fully with all sub-levels (although my player is at the same co-ordinates they were in the transition room, not at the player start point for some reason).
Am I missing something about transition levels? They seem like the ideal solution for a loading screen, but there is no documentation to be found 
Thanks!
Edit:
Extra bits from the log:
LogWorld: ----SeamlessTravel finished------
LogGameMode: >> GameMode::HandleSeamlessTravelPlayer: PlayerController_6
LogGameMode: Warning - PATHS NOT DEFINED or NO PLAYERSTART with positive rating
LogGameMode: << GameMode::HandleSeamlessTravelPlayer: PlayerController_6
LogLevelStreaming: World to duplicate for PIE ‘/Game/Maps/Globals’ not found. Attempting load.
One of my sub-levels is called Globals, which is also loaded up in the previous scene, but the “PATHS NOT DEFINED” error I believe is basically it not finding the PlayerStart object (which would explain why in Standalone my player is in the floor).