when I made my turkey cake I did a crumb coating with indydebi's icing (delicious!) then after it was crusted I applied the final buttercream. I had problems with it. Although the buttercream was hard to the touch when I used viva in some places it lifted the buttercream. then I put it back for few more minutes and used hot spatula technique but I couldn't get a smooth finish. Is there another way to smooth odd shaped cakes an easier way? and what causes lifting of the icing? could it be that the crumbcoat was set too much and was dried out and so the next layer of icing just didn't stick to it?
I think you're right about the icing being too dried out so the underneath stuck. I smooth my icing (Indydebi's, of course!) within 10 minutes of putting it on the cake and I don't refrigerator it first. I just leave it sit on the counter while I'm cleaning up or something and then within a few minutes I smooth it. I've never done a crumb coat though, so maybe that is the difference.
It could be that those places were not as crusted over as the other parts of it. It shouldn't stick and lift off the cake if it is crusted.