Landscape with holes

I tried a shipping build.
Some landscapes have holes. They are distance dependent.
I just see that the mushrooms have no material.
The level is automatically generated from many streaming levels. The levels are loaded with “CreateInstance”.
In Standalone or PIE there are no problems.
How can I fix the problem?

Edit:
I set the “Skylight” to “moveable” and it was acceptable. Even so, it is still that many of the landscapes are faded out according to the distance. Since it’s a sidescroller, that’s not too bad, but it certainly shouldn’t be.