I teach the Wilton decorating classes and told my level 1 students (who have not been taught royal icing) that they could pipe flowers out in buttercream and place these in the freezer. Which would allow easier transfering- However, 2 of my students stated that they tried to do this at home and that their buttercream never froze! One said she put it in for 24 hours and that when she took them out they were still soft like reg icing and the other said hers were really soft. Why did this happen? I have done this and did not have this occur!

Please give me ideas why this happened!

dont know... do know that my bc (indydebis) doesnt freeze solid. i know stuff like meringue doesnt freeze solid either.
i believe bc flowers car air dry and become pretty solid too though.
xx