When StartUpMovie is set, the level instance to which the CesiumSubLevel component is attached is not loaded

Using the new version 2.0.0, we created a scene that moves between level instances to which the CesiumSubLevel component in Google Photorealistic 3D tiles is attached.

When this scene is packaged and executed with the startup movie set up, the movie plays and crashes with the following message.

・StartUpMovie Settings

LogWindows: Error: appError called: Assertion failed: !LoadingLevelInstances.Contains(LevelInstanceID) [File:D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\LevelInstance\LevelInstanceSubsystem.cpp] [Line: 373]

The level instance will load normally if the startup movie is not set.
We also used Bink Media for encoding the movie, but the normal method of using .mp4 also does not load the level and crashes.

Is this a bug? Or is there a solution? Thank you in advance.
(We use DeepL translation because our native language is not English. Sorry if it is hard to read.)

Hi @YRU2,

I think this may be a bug, but we’d have to investigate further. Do you have a minimal example that we can use to reproduce this?

In other words, can you give us step-by-step instructions for setting up the scene, in a way that reproduces the crash?

Thanks for the reply.

  1. Create a new project, create two blank levels and place them as level instances on the main level, then attach the Cesium SubLevelComponent.

  2. Prepare an appropriate movie file and set it as the startup movie from the project settings.

3.Package the project.

  1. After the packaging is completed and the project is launched, the startup movie will be played. After the movie finishes playing, a crash occurs.

Incidentally, the project without the CesiumSubLevel component did not crash when the startup movie was set up.

This seems to happen when the CesiumSubLevel component is used.

Hello, I am trying to reproduce the error. When I add the blank levels as level instances in the main level, the details panel shows that the root component is a LevelInstanceComponent. In your screenshot, the root component instead says “RootComponent (Root)”. Is that component a LevelInstanceComponent or is it a USceneComponent?

What version of Unreal Engine are you using?

Does adding a startup movie cause a crash for you in the Sublevel example in cesium-unreal-samples?