Chronic777 - you are not alone. I notice the smell comes back back some if you start to open/close the jar frequently in a short period of time. I haven't been able to figure out why this problem occurs to us. Hopefully more chime in...
Air is an integral part of the curing process. Depending on the density of the product and the volume of product inside the jar, one could come across an instance where the quantity of remaining air is not sufficient. You may find that the effect diminishes, as the product is cured for a longer period.
Simon