I have this happen to my BC cakes pretty often. My cakes are never "cold" when I apply the BC. I always freeze my cakes after baking, but I always allow them to thaw covered for several hrs (@ least 6hrs). I fill my cakes & crumb coat and after they crust, cover with Saran Wrap & let set. I place a same size cake pan on top with a wgt to increase the settling process. I let them settle for 2-3 hrs. It would probably be better to let them settle longer, but I usually don't have time. Before I put the final BC coat on, I unwrap the cake & let air dry.
I think (I may be wrong) that my problem is the use of the large icing tip that i use to apply the BC before smoothing. It may create air btw the BC & the cake.
The cake "farts" aren't really a big deal to me anymore. I usually notice them right away with smoothing, and remove them by piercing through the BC & into the cake with a small skewer. After I make the small hole, I smooth in opposite directions with a Viva towel and fondant smoother. The air is released and it's barely noticeable if you smooth enough.