I've been using the Wilton Buttercream recipes, for both vanilla and chocolate icing, forever. I thought they were typical for buttercream icings. Boy, was I wrong!
Yesterday I made a cake for my family, using recipes I had never used before. WASC (two nine-inch round layers) with Whimsical Bakehouse's Cookies 'n Cream filling and their House Buttercream. Then I made chocolate transfer sunflowers and bugs from the WBH cookbook. The cake was very cute. (I'm working my way through it with my fork now.) It is so delicious and light, and the buttercream is as fluffy as a cloud.
There is one problem, however. After I cut out about three slices, the remaining cake split right down the middle. (I did let the cake cool for at least seven hours before filling and icing.) I've never had this happen before, and I've never used WASC before. Is this somehing that happens with WASC? Does anyone know what happened?
Any tips or hints would be appreciated. Thanks.

I've never had that problem w/ WASC before. Unfortunately I don't know what the problem could have been. Sorry, just know that it's not typical in my experience. Hopefully someone else can give you some insight.