Three days after making this cake it started to seep red liquid from the corners on the base. On tasting, it is quite obvious that the fondant on the inside is dissolving.  Whilst the weather has been hot and a little humid it has not been too bad and the fondant on the outside of the cake is totally dry.  My initial thoughts were that maybe, for some reason, the alcohol in the fruit cake was dissolving the icing and on researching the topic this is the only decent answer that someone else had, that I could find. That person's suggestion was to use a layer of almond icing under the fondant and that would stop the problem.  However, 5 years ago this happened to me, and that cake had almond icing on it.  When that cake was cut, 3 weeks after it was made, the almond icing had totally dissolved and you would never have known that it had this layer under the fondant.

I must say this has me totally flummoxed.  Two cakes in 5 years.  Same fruitcake recipe, different icing and different brands.  Humidity has been a lot worse and never affected my cakes. I make and ice this fruitcake with just fondant on a regular basis.

Help, any suggestions, no matter how far fetched, gratefully accepted.

You need to let the cake sit for a few weeks at room temperature after the last dose of liquor to make sure there is no residual liquid near the surface.

Sometime when the cake is too cold, it doesn't age properly (butter hardens up) and there are wet spots of the added liquor.  The fridge is too cold a place for fruitcake to age well.

I never age my fruit cakes in the fridge.  I leave them wrapped in foil on the dining room bench.  I see no reason what so ever to put any fruit cake that I make in the fridge.

Apart from brushing the surface of the cake with alcohol as soon as it comes out of the oven I do not add any more as the fruit has been soaking it it for day to weeks before I make the cake.

I generally let my cakes sit for about a week to firm up well before I ice them.

I did wonder if it happened with this cake because it had been carved and had no firm cake edges and hence the fruit was in contact with the icing.  This however did not apply to the previous cake, which had cake tin edges.