Banding after light bake inquiry

sl4
sl5
Getting banding post bake. Any idea why they’re showing up? They show up on production quality bakes as well just with more defined rings. It appears more obvious in this small room. in the larger room its not as obvious but still there. Lightmap channel and resolution are all fine, with ample padding no overlap liughtmap uvs. PLeeeease need assistance. Lightmass world settings scale and quality are also at proper ratio. (.1,10 or .2,5) respectively.