Summary: There is a visual bug available in Single Player or MP. While standing 10 meters from the shore, my torch is somehow projecting a weird smeary bloom onto the distant water.
Where this bloom intersects with the distant shore, as you move your character left and right, there is visual bleed along the shoreline. During this shore smeary-bleed process my “locked-in” framerate takes a slight hit.
I think it is an older bug, not just testlive. I had this with the Breath of the Red Mother, and when running/gallopping in shallow waters, the reflection is visible until the end of the body of water.
I’ve had this happen in my game for a good while now so it’s definitely not just a testlive thing. It’s probably something as simple as the light/particles for torches aren’t being ignored by the screenspace reflections.