Kerry - Thanks for the advice - I'll try this next time.
I am wondering if the temperature of the mold might to an issue. Greweling says to heat the molds to 80 F before filling them, although he says this step is optional. My kitchen is cool - usually 667 - 68 F unless the oven and or wood stove are on. The new mold is MUCH heavier than my other molds so I am wondering if the cold plastic is throwing the chocolate out of temper. Since I had never warmed my other molds and never had problems it didn't occur to me to warm this one.