Error in build when using subscene workflow

Hi !

I just wonder if anyone has the same problem :
I use an empty project, with only Main camera & light.

I add : subscene, and a cube in the subscene to make it automattically converted to an entity, everything works fine in editor.
But in external build, the subscene doesn't load :/ The error tell that i need to use the new BuildConfigurationAsset in order to load subscene
If anyone can't push me in the right direction :/