Are these cotyledon spots normal?

[JoeP]

Can someone tell me if the black spots on the yellowing cotyledons are normal?

Last year was my first time starting from seed. I know that after a set or two of true leaves the cotyledon’s will yellow and eventually fall off but I don’t remember if the black spots are normal.

I may be guilty of overwatering. I was watering with a spray bottle every other day when the top of the seed starting medium appeared dry. They are inside, under lights, and the temp fluctuates between 63 and 72 degrees. They have not yet been exposed to direct sunlight. I did have one corner of the flat on a heat mat to germinate pepper seeds. I used the heat mat to germinate the tomatoes too but removed it once they sprouted.

Thanks,
JoeP