Hi H, seems like a familiar look with the DT final coats. Give the body a light rub with super fine steel wool and try and knock off any high points. It's a bit hard to see with the reflection if the marks are pores or high points.
I don't think you have applied it too thin. Sometimes tiny pieces of the cloth you are using stick to the coat or tiny particles stick to it when curing. You will always get a smoother finish when you grain fill prior.