Are you stirring the varnish thouroughly? Varnishes have chemical agents in them to control the sheen. If you open a can of satin varnish and just start varnishing, the varnish in the top of the can will dry high gloss, the varnish in the bottom will dry dull. You will see a cloudy substance at the bottom of lower sheen varnishes. This is what controls the sheen.

Are you leaning the doors up against a wall while drying? It is important that varnish dry uniformly with equal air movement and heat distribution over the whole surface.