Thank you so much, Elisabete! With a lot of help from the cake community, I believe I have found the culprit. I have been using homemade cake release (1 part vegetable oil, 1 part Crisco and 1 part flour) and it seems the oil in the mixture was causing the problem. I made both the mustache cake and the painted buttercream cake without the cake release and they both worked perfectly.
Sugar Sugar by SSmiley
