AI made an almond and butterscotch cake, and thought a caramel filling would go well with it.

I made SMBC and added some Nestlé top'n'fill, which is a commercial caramel in a tin. The taste of the filling with the caramel added was very nice. I torted my cake, and had enough caramel SMBC leftover to decorate some cupcakes that were also made with the almond and butterscotch batter.

The cupcakes were delicious! The caramel flavour came through very nicely. I was so looking forward to trying the cake. Today I served the cake to guests, and although it tasted fine - no-one could taste any of the caramel flavour. I was so disappointed! I'm not sure what happened. The cake was torted and ganached on Thursday, and covered in fondant and decorated on Friday, and then sat until today when it was served. What happened to my caramel flavour? Any ideas?