Is it normal for liquid to separate from buttercream when it is stored? This happens in my white or colored icing, always, after a day or so. I’ve attached a photo of some I’ve got in a bowl. 

I’ve also had some separation once the buttercream is on a cake, after about 24 hours or more, particularly if the cake is really moist. 

I use Indydebi’s buttercream and love it! So I don’t want to change recipes!

Thanks!

It is normal my dear, since buttercream is an emulsion. Every emulsion has an oil-based phase (butter, Crisco, margarine, etc) and an aqueous phase (water, milk, cream, non-dairy creamer, etc), they naturally do not love each other and always fight until they split. The presence of emulsifying agents present in the formula will add stability. Unless you add an emulsifying agent to your buttercream, such a polymer or lecithin, which is very unlikely, the only reason why your buttercream is holding together is the viscosity (thickness) that the sugar and fat create when they mix, also, the sugar helps retaining the liquid into the fatty matrix. Also, some fats, like butter, naturally carry little amounts of natural emulsifiers that help the stability. In the case of the typical American buttercream, yes, it is normal for some liquid to separate, give it a gentle mix to emulsify the whole thing without adding too much air. 

And yes, I'm a mad scientist in the kitchen, happy to help!

Good to know…thank you for sharing such detailed information.   It happened to me often when I don’t fridge my b’cream for a couple days.  Often wondered why  :) 

Oh sure, a room temperature buttercream will separate even faster, as the fatty phase gets softer and hence, less thick. Also, if your buttercream is very sugary and the moisture is high, some of that moisture might end up in your buttercream if not properly covered.