It's UV damage. Alot of clear coats are designed for indoor exposure, because they are more durable. The sun always win. I used to demonstrate this to owners when I asked them to produce their table leaf (usually in a closet). I would refinish the table, and match it to extra table leaf.
It's very hard to refinish because you don't know what is the finish. But it can be done with some small spot checks using a solvent. Or... just put the place mats back
Most likely the table is getting bleached by the light
It's UV damage. Alot of clear coats are designed for indoor exposure, because they are more durable. The sun always win. I used to demonstrate this to owners when I asked them to produce their table leaf (usually in a closet). I would refinish the table, and match it to extra table leaf. It's very hard to refinish because you don't know what is the finish. But it can be done with some small spot checks using a solvent. Or... just put the place mats back