Why does level instance have different lighting?

I have a landscape with a landscape material, a basic scene lighting setup with sunlight, sky sphere, and sky atmosphere, infinite post processing volume, and a few reflection captures. I also have turned on “force no precomputed lighting.”

I got a gas station pack from the marketplace. I opened up the demo level, and selected all the static meshes, and saved them as a level instance, to make it easy to move the entire thing into my own level. I then placed this sub-level into my own level.

After doing this, I placed a few of the ground block static mesh instances from the asset pack into my own level (not the sub-level) – and they are lit totally differently.
I’ve verified the blocks in the level instance use the same mesh and material.

So, what should I go spelunking for to figure out why the same mesh in the level instance, has totally different lighting (or is otherwise much darker) than in the main level?