The light flickers on this corner. (it may be hard to see)
Using the light debugger, it seems that the bottom-left light ray is sometimes reflected off the vertex of the wall - for some reason the right light ray doesn’t.
For anyone looking, the image is a .gif, there is a very faint red moving shadow in the image.
@MashyZ , please redo the .gif, with better lighting contrast so it’s very apparent what’s happening. And are you dragging the light source around? Its nigh on impossible to tell what’s going on with the light source. Maybe explain what you are doing?