UE5 Graphic bugs when rendering Screenshot or Movie in 4k or higher res

Hi unreal community,

I´m having issues rendering my archviz projects as a Picture or Movie. i´m Using the high resolution screenshot tool and as soon as I set the multiplier to 3x I get strange rectangular lights and shadows all over my scenes. see images




I´m getting the same problems when rendering a png sequence with the movie render queue set to 4k. I´m using a 3090 so i shouldn´t be hardware limited.

when i´m rendering in Full HD with the movie render queue or take a highresscreen up to 2x images look fine. I already tried setting the highres screenshot delay to up to 1000 or use warmup frames when using movie render queue but it doesn´t help.

I need Highres for large scale prints. Any help is really appreciated, as i need to deliver my work soon and hope I´ll find a solution in UE5. otherwise I guess I´ll need to redo the scenes in UE4 or render images and movies in blender cycles which would take forever…