Reflection problem on UE4.18 and UE4.18.1

Recently I started learning Unreal Engine for archviz.
For learning purpose I made a test room to analyse lightning, shadows and materials.

Everything was going good but recently I downloaded the latest version 4.18 and then updated it to 4.18.1 .
Reflection in model in 4.17 was great but when I opened the project in 4.18 there was loss in reflection and ugly reflection on test spheres as you can see in screenshot.
Even making the room freshly in 4.18 didn’t help and same problems were encountered as I updated to 4.18.1 .
​​​​​​​I would be highly thankful for a solution to this problem.

Build 4.17

Build 4.18