Reflection dissapears, how to fix?

Why is the reflection on the floor dissapear when there is an uphill?

I’ve tried different maps and found a similarity, when the angle of the camera and floor gets smaller, like uphill, reflection dissapears, when the angle keeps growing, the area of missing reflection grows too.

What exactly cause the problem, camera or material or reflcetion?

I’ve searched in the forum and someone met the same problem but it doesn’t solved yet.

Thanks for the support in the forum