I use 30 minute epoxy mixed with iso alcohol to fuel proof and have never had any problems with it drying. I agree with Joe. maybe you put too much alcohol in and the water is pushing the oil out. It only needs to be thinned enough to be able to be brushed on. It doesn't take much. I would gently rub it down with alcohol to see if that helps, but if it seems the epoxy has dried underneath, I would go ahead and get in the air and periodicly check to make sure the coating is still there.

Good Luck