Streaking Behaviour of Lights - Render but not Viewport

Question

My scene in the viewport looks like this:

But the render comes out like this (hopefully the jpeg's not too bad):

I have no hidden lights, no random meshes. There should be no reason the lights "smear" as they do. I've thought about hiding the light from the reflection rays with the light path node, but I'm not sure how to do that and it seems entirely unnecessary. I see the second light from the left's reflection on the plane, but that's pretty easily solved (in the viewport, anyway) by just moving it back a bit. There's no weird compositing things going on either.

What's going on? Thanks.

Answer 1

It looks like the render is the physically correct way to render lights over that kind of surface. Looking up reference images of sunsets over an ocean show similar effects. To make the light not travel that far down the surface of your floor, you'll likely need to lower the power of the lights.

I wonder if the floor has a modifier on it that changes it's displacement that would only show up on a real render, and not in your viewport.