Did I understand correctly that I need to create custom Parent Player State and then make two children out of it for both Menu Player State and Game Session Player State?
I tried this method as well, but my CopyProperties event in old Player State continues to return old “Menu” Player State but the new “Session” one…
I’ve set the seamless travel=true inside MenuGameMode and I use Standalone simulation as I am awared of the seamless not working in PIE. Transition map is set as well.
Seamless Travel checkbox in WB_LobbyMenu
Launch properties:

Transition map setup with loading screen:
Menu Game Mode defaults:

Session Game Mode defaults:




