Vacuum packing creates a low oxygen, but not an anaerobic environment. This does cut off enough oxygen to stop further blue mold development, but (as with any cheese) aging, proteolysis, lipolysis, etc keep going full speed ahead if they are maintained at cave temperature. What you want to do is get the blue going really well, pierce, let it go a couple of more weeks to get internal blueing and then I vac bag. I will then hold it at cave temperature until it reaches the desired level of ripeness. Then you have to get it into refrigeration temperature to slow everything down.