Why is my sky reflecting on water and chrome faces that are underground?

Development Rendering
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1

I have an 18 storeys model with 7 that are UNDERGROUND with no visual connections to the outer sky. Original model made in SKU19 imported as an FBX file

Yet when I look at chrome surfaces and water, like a

THISlakeWATERisNOTexposedTOrealSKYwhyISitREFLECTINGit
THISlakeWATERisNOTexposedTOrealSKYwhyISitREFLECTINGit1913×1003 114 KB

swimming pool / lake I see the reflections of the sky.
Why is that and how to stop it?

2

Similar problem baffled me for a while. It seems to depend on the rendering method I used. Path tracing and LUMEN with Real Time removed the problem. Without LUMEN, the neighbor was in my mirror.