Artifact Lighting on Mesh

Hello everyone,
Thanks for those who will have the patience to look into my problem.

To set the context, I have a problem that only occurs when I place a light on or near a mesh.
When this happens, it causes the rendering below:

Design sans titre

I call them artifacts, but I don’t know how to describe them properly, but overall, it creates a kind of wave reflection on all the mesh around it.

I’m still a beginner on unreal and I don’t think I’ve fully understood how the lights work, so I’ve tried a few things, not least the shadow settings, but nothing has worked.

If you have any ideas on how to correct the problem I’d be extremely grateful.
Thanks again and have a nice day.