Repro:

1. Create a blank project using Built-In or HDRP
2. Create a plane in order to receive lightmaps, make it Lightmap Static
3. Generate Lighting
4. Navigate to the SceneName folder and locate Lightmap__comp_light.exr
5. Select the asset in the Project View
6. Ensure that the Inspector is visible

Note:

The preview for the lightmap asset will look something like the attached image. Where I need to see an exposure slider, there is only a slider to control the mipmap preview level.

This also affects Reflection Probes. This makes both ref. probes and lightmaps impossible to debug in the Editor Instead they will need to be viewed in an external package for debugging. Not ideal.