All of a sudden I'm starting to have crazy problems with my fondant covered cakes.  They all have ridges in them, and the last one I did got all kinds of lumps, bumps, and cracks right down to the buttercream.  Any help in figuring out what is going on would be greatly appreciated.  I have multiple fondant covered cake orders coming up and my customers expect better than this, as do I!  It's down right embarrassing!

A few details first:  my cakes are a doctored cake mix (1 mix, 1 box pudding, 4 eggs, milk & oil).  Nothing has changed with that except I got a new oven quite a while ago and started baking with convection.  My buttercream is 1/2 shortening 1/2 butter, 1.5lb powdered sugar, nothing new with that recipe either.  I make marshmallow fondant with corn syrup and glycerin added.  Have covered many many cakes with this without a problem.

Changes I have made/possible reasons- 1.started weighting my cakes overnight to reduce the "bulge" issue, but seems to make it worse?  2. Switched to Americolor soft gel food coloring- using small amounts but makes fondant more sticky than wilton coloring  3.  It is way way humid and hot here lately, and we didn't have our air conditioners in until the last cake was done.  I'll post a few pics of the problem cakes below.  Not all were done in super hot weather, and not all were done just with americolor.  

Things I thought were causing it and attempted to correct-  1. Buttercream crumb coat under fondant too thin- made thicker but didn't help the next cake either 2.  Stiffer buttercream- still didn't seem to help 3.  Stiffer dam- still not helping 2.  Fondant rolled too thin- tried thicker but still a problem

Looking at the pics now it almost seems that I'm seeing the cake, and where the filling is is where it is indented?  Could that be from weighting the cakes overnight?  Is it expanding and then "sucking" the fondant in with it?  The curious george cake was a different kind of mess, so I think something else was going on too.  The fondant was crumbly and yet still soft, both tiers were perfectly level and the sides were straight before the fondant went on, but got lumpy and messy under the fondant. I peeled off & recovered the smaller tier but it was still bad, and I made a whole new batch of fondant for the bottom tier.  It was better, but still seemed to fall apart once I added the Americolor. I was so upset and embarrassed, but, as a side note, the customer loved it and said everyone wanted to know who made it and if they could have my number.  Said it was the best cake they've ever tasted.  We are our own worst critics, but I know I CAN do better!  I've never had these issues with my cakes before.  Slight bulge yes, but never lumpy like this!  I want those beautiful straight sides!  Help please! Thanks!

Cute cakes! Don't know if this will help, but here's what i do:

1) Completely ice cake and push down the layers some manually (careful not to crack the cake)

2)Let it sit out 5 hours

3) refrigerate overnight

4) next day, I take the cake out and scrape the bulges (from sitting out 5 hours) with a straight edge (bowl scrapers)

5) apply fondant

6) if it's especially humid, the fondant may stretch, so I leave room for that at the base and cut more fondant off if necessary

When using a fruit filling, I make a half inch diameter dam with icing so thick you could mold it into shapes and set it about 1/4 in inside the outer edge

AI had an off weekend also! Sounds like it may be a humidity issue? Maybe the buttercream was too soft and sticky? It cld have also affected your fondant? I also make my own MMF but without the glycerin and noticed that if I over heat the marshmallows they make very toughd dry fondant. Idk if any of this helps lol! I'm always learning something new.

Your cakes are adorable though! Dnt be too hard on yourself!

Did this stuff happen before or after you stacked your cakes?  What kind of support are you using?

How thin is your fondant rolled?  Are you using a mat to roll out the fondant or on the counter top?  You can use corn starch to help with the stickiness issue when rolling it out, which will help dry it out, rather than adding to the sticky issue like powdered sugar can.

AThanks for the responses and the compliments on the cakes!

I do think multiple factors are at play here. I roll out the fondant on the clean glass table that has been sprinkled with powdered sugar. Has not been an issue until now, but I'm willing to try something new. I did pull out the corn starch with the curious George cake, but I think the fondant was too far gone by then. The first attempt at covering the smaller tier was rolled to about 1/16, the second time was 1/8 of an inch. They were showing the ridges right away, without anything being stacked. I used the SPS system for all of these, and there was definitely no weight from the top to on the bottom ones.

I definitely could have overheated the marshmallows. That whole batch was awful! I will make sure to avoid that in the future. I'm also remembering that even though the frosting was crusted before I placed the fondant on, it was sort of damp. Maybe there was more condensation than usual and it started to melt the already bad batch of fondant when I put it on? I know some people place fondant on frozen cakes to get sharp edges, but that scares me!

Next time I will make sure I don't overheat the marshmallows, will try corn starch for rolling out, and I think I will not weight the cakes. Seems I had better luck without that step. Fingers crossed this works! If it doesn't, I just might have to switch to ganache for under fondant, or will that melt too?

Thanks again everyone!