More often than not my cakes stay at room temp and I have had problems with these. I find I have them more often in the summer months or when my house is too warm.
In my case they never really appeared until the next morning or after I'd moved the cake around several times or even traveled with it. So I think it has something to do with the cakes moving and maybe shifting that the gas try to escape.
I've gotten to where after I crumb coat and let my cake sit that I actually pick the cake and board up off the counter a few inches and drop it down a couple of times. In my mind this pushes out any extra air. Of course it could be all in my head.
I had several do this to me last summer, including a wedding cake. It is enough to make you want to quit, but please don't give up yet.