Issue #29847: East Entrance to Nuka-Town Missing Textures and Garden Terrace Ceiling next monorail missing texture
Two locations in the Nuka World DLC are missing Ceiling textures, East Entrance to Nuka-Town near fizztop mountain, as well as the elevator entrance below the monorail is missing a ceiling texture as well.
There is a mod that provides a solutions to these to issues. Appears that the mod author is just reusing assets so may be able to include in the Patch. The mod description page shows before after screen shots as well.
Nuka-World - Fixes the East Entrance to Nuka-Town USA near Fizztop Mountain