Yea that isn't just sunlight. That is out in the sun on a hot day for hours, or in a hot car for hours, or something like that where the thing got to 120+ degrees for an extended period. I cannot see that this would damage the coin; its a low temp for a coin but a high temp for the plastic.
A microwave could scar a coin. Silver or gold may be damaged; not sure how hot it actually gets on high, but metal gets rather hot fast in there, and those arcs & sparks cut the metal layer out of a cd in a hurry.