I know that a bunch of badges were at the engravers before the holidays, and he was going to check on them.
If it's been 4 months since you mailed in your blue card, contact him directly. AFAIK, while batches are best, he doesn't wait just because...
If there was a reason yours was recieved but not processed, you'd have heard by now. Odds are if you have sent in your Blue card before Dec 10th, it's been engraved. The holidays are busy, but if he's gotten them back, they will be mailed out quickly.