tinajhung

I've been painting chocolate molds with tempered cocoa butter and molding them with chocolate. Are the chocolate shells supposed to release after the chocolate is set? I often see that on Instagram, but mine doesn't release unless I shock the molds in the freezer for 15-20 min. Should I fill the molds, close them before placing them in the freezers? Or are the shell (unfilled) supposed to shrink as a sign of being properly tempered?