Assetbundle very dark in Build game, but look correct in Editor ??

I am trying to load a assetbundle of a scene in my game. When I load the assetbundle into Unity Editor the result appears correct. When I build the game and load the same assetbundle the scene appears dark with opaque shadows.

Editor (Expected result):

Game build:

The assetbundle was created using Unity 2019.4.40f1
The game was built using the same Unity 2019.4.40f1

Both use linear color space, I have checked quality settings are same for editor and build. Am very sure the shaders were included with the assetbundle.

What could be causing scene assetbundles to be so dark when loaded in build game but work perfectly in Editor??

These are the lighting settings of the assetbundle:

The solution was to change Lightmap mode from Automatic to Custom and ensure the Realtime Directional checkbox was enabled: