I have looked online for solutions to this issue. Some other posts on the forums mentioned rebuilding my lighting to remove the preview icon from my textures. I tried that amongst other things but none of it worked.
Here is what I am seeing on all of my textures. I use one point light that is moveable and Ultra Dynamic Sky / Weather plugin.
I have Lumen enabled with Ray Lighting mode set to Surface Cache and Software Tracing set to Detail.