Reflections misbehaving in SM4 in UE4.18/4.18.1

In UE4.17 , reflection in shading model 4 (Under setting > preview rendering level > SM4) was working absolutely fine.

But recently after downloading UE4.18 reflections are misbehaving as shown in screenshots but problem is only in Shading Model 4 not Shading Model 5.

I thought my pc have some issues so I tried it on my friends pc and same problems was encountered in SM4 but in SM5 works fine.

I have quite an old PC(don’t laugh at it!) Xeon E5440 (quad core 2.83GHz), ECS G31 board , 4Gb ram and Nvedia 8400gs, which only supports Shading Model 4. You might say this hardware is incompatible but it works perfect for learning purpose till UE4.17, right now I don’t have any plan to upgrade my pc because I am a student.

Before I knew the root cause of the problem I posted my problem at

Build 4.17 (SM4):

Build 4.18(SM4):

Thank you for your report. We will begin investigation into this issue as soon as possible. If we are unable to reproduce the problem, or need more information, we will follow up with some additional questions for you. Otherwise, we will post an ‘Answer’ once the issue has been logged in our bug database or we have a solution for it.

Buddy have you reproduced the bug?

If not just open a model with some reflections in 4.18 and just change the shading model in preview rendering level from SM5 to SM4 and you will see the problem.

Hi mohdzubair, Thank you for submitting this bug report. I have reproduced this issue and logged a report for it here at JIRA UE-53187. You can track the report’s status as the issue is reviewed by our development staff. Please be aware that this issue may not be prioritized or fixed soon.