UE 4.9 opening level problem

I created my project in UE 4.8 then i upgraded to 4.9
When i run the game in editor everything works fine.
When i pack project and open it, it does something weird.

At the end of the level i have a trigger box that should open next level. (Blueprint: OnActorBeginOverlap–>OpenLevel)
Instead of doing that, game is loading the same level that i am already in.
In Ver. 4.8 everything was working fine.

Anybody has an idea of what is going on?