Can anyone identify the cause of these strange shadows?
They are appearing on a mesh in one of my levels but not another (where I do see circular shadows but they are not even close to this level of distorted)
Looks like distance field ambient occlusion or distance field shadows. You can disable them on a mesh, increase the resolution of them, or try constructing assets in ways that handle distance fields better.
It does indeed seem to be caused by distance field lighting, thought I couldn’t find the exact settings to get it working nicely so I’ve disabled “Affect Distance Field Lighting” and that has removed the distortion.
I suppose it’s due to my scaling up of this mesh and landscape and on larger meshes I’d want proportionate resolution, though I didn’t find the precise settings to do so without re-building my scene’s lighting. Will give this a bit more research and update when I find the proper settings to adjust.
I had a similar problem with you, and what solved it was indeed changing the scale from inside the static mesh properties (and the reducing the scale in-editor). Open the static mesh, go to Details → Build Settings → Build Scale, and try increasing the value there and see what happens. Another value you can try changing is the Distance Field Self Shadow Bias. Hope that helps somehow!