Mine do that also but it is worse with a mix. I also try to turn mine as early as possible and if I don't think they are cooked I turn them back on the first side, I think it is when the batter sets up.
This batter comes out thinner than some but works good for making nicer looking cakes.
1 c. sifted flour
1Tsp. baking powder
3 Tbsp. melted butter
1 tsp. vanilla
2 Tbsp. sugar
1 c. milk
Mix dry ingredients in one bowl and liquids in a separate bowl pour and mix dry ingredients into liquids gradually cook on ungreased skillet.
Maybe they come out better since they have so much butter.