Rotating lights disables shadows

Hello folks,

Just the other day I got my hands on Unreal (4.9.2) again and wanted to set up a small scene with some assets I modelled in Maya and textured in Substance Painter.

A friend (very skilled in Unreal) helped me set up a scene, but towards the end, we noticed that there were no shadows to be seen. After some testing and googling many questions and having tried basically all the solutions provided, I noticed that in a blank, new project, there are shadows HOWEVER they disappear the second I rotate any of the two lights in the scene. For one split-second (or frame if you will), it shows a darkness, then returns to the previous lighting but this time with no shadows and they never come back: even deleting the old lights and putting in new ones does not work.

My Engine Scalability settings are still set to Epic.

Any ideas?

Top picture shows the current look without any shadows. Second picture shows the single frame of darkness that occurs when I try to rotate a light before it snaps back to the first picture.