I'm working on a wedding cake for tomorrow; my 10 inch is giving me an immense amount of grief. It's apple cake with cream cheese frosting. I made cream cheese SMBC which I've never had problems with before. Yesterday, it refused to set and about an hour after I frosted the cake it slid off the side. So I scraped it and redid it with a very firm vanilla SMBC. All looked well so I fondanted today. About 6 hours later when I went back to decorate, I noticed a huge air pocket and it would not go down. I ended up taking the fondant off and the frosting was again falling off the side of the cake. Only in one spot. I am completely stumped as to why this keeps happening. Does anyone have any ideas that could help? I don't think I can get the layers apart to re-stack and I don't really have enough time to rebake. My current thought is to make a very stiff powdered sugar buttercream and put it on in hopes that the crusting will keep everything together. The layers aren't shifting but something is breaking down my butter creams. I'd love any ideas or suggestions! Thanks!

Update-Just separated the layers and re-filled with smbc. it's chilling now...hoping that'll work!

If it does it again in that spot, try brushing a little piping gel on the spot and then icing it. Maybe even brush a little on that spot once the icing has crusted, just to help the fondant adhere.

Oh please keep us updated as to how it all works out.
Sorry I have no ideas on how to help you.

I would have to say it's the carrot cake causing moisture that is making your icing slip. I would make a stiff buttercream and even let the wiped off cake 'air out' a bit before applying the icing next time. Hope you got it together. next time you have a bubble, you can try to poke with a needle and let the air out but the fondant has to be fresh. I had to redo an entire wedding cake over this year due to moist cakes and humidity!
hope you didn't pull all your hair out!

Thanks everyone!

Update-It was actually an apple cake, not carrot. I still can't figure out why the icing was sliding off the cake but so far (*knock**knock**knock*) all is well. Oddly enough it's only happening to one of the apple cakes.

After scraping and re-stacking and icing, letting it sit for a while then refondanting I decorated and all seems well. It's been sitting for maybe 3-4 hours and no signs of bubbles or softening. Hopefully it will still be beautiful in the morning!

How nerve wracking for you! I hope all goes well.