Quoted from Nepi23:I am in the middle of installing a PF protector. Have you noticed similar phenomenon, it looks like there is moisture under the PF protector. I had waxed the playfield, but had not removed the wax before putting the PF protector in - might this be the reason for it? Or if this is not the reason, how to avoid the phenomenon?
This is not moisture and not from a chemical. The are newton rings caused by refraction of light between two materials. Check the previous threads on this. A bit annoying but not an issue.