Food in fridge freezing

Food in fridge is freezing even after turning down the temperature control. Does anyone know what causes this?

The fridge gets its cold air from the freezer through a vent between the freezer and fridge.The fan in the freezer blows air through it. There is a flap you adjust with the fridge temp. control. Make sure it’s closing when you adjust the temp.

Your damper control is part 115 on diagram 2