RAYZOON

When load a kit, lighting of 3D kit is brighter than its value until it's changed.

If it's 'Normal', lighting is brighter than 'Normal' until I select lighting mode 'Normal' again or something else.
Likewise, If it's 'Uniform', lighting is brighter than 'Uniform' until I select lighting mode 'Uniform' again or something else.
This goes for all lighting mode.

Is it normal? or known issue?

I never noticed that before but you are correct. I'm sure Ralph will see your post here and decide if this requires some tweaking.

Known issue that should be resolved in the next update.