I was wondering why this is happening to my mmf. I barely put any bc in between the layers and was careful to not go all the way to the edge, but the mmf still bulged. I used the sps bakery crafts stacking system. The layers were 10", 8", and 6" WASC.
ALSO WHAT WOULD YOU CHARGE FOR THIS CAKE, I HAVE NEVER HAD ANYONE PAY FOR A CAKE YET BUT A LADY AT THE PARTY WAS INTERESTED.
*THREE TIERED FLOWER GARDEN CAKE IN MY PHOTOS
*I DON'T KNOW HOW TO RESIZE IT TO UPLOAD SORRY.

It helps to allow the fondant to settle on the layer, before final trimming and adding dowels. The weight of the fondant will press down on the cake just enough to cause the bulge.

Then, cut the dowels even with the fondant to they don't allow the cake to add more weight to the lower layers.

Make sure you have a really good stiff icing dam and then it doesn't matter how much filling you have. Also, I would put a little weight on top. May be a dinner plate and let it sit that way for an hour, just so it can settle under the weight before you put the fondant or icing on. That way you can go back and spackle that bump if you need to.