Uh oh, I didn't need any more reason to look at the new 11" model...I would get that addressed as soon as possible or sell it
Mine started out like that then the spots just started increasing after a few weeks of use to the point my screen started looking like it had measles. My iPad Pro got sold for a quarter of the price it would have gone for had I sold it when it had just 1 spot.
The spot is a sign that your screen is delaminating.