I hate to say it, but since Terry Makedon left the AMD driver team it just hasn't felt the same and if there was any situation that would cause AMD to miss a month it was going to be that and while it's been a while since he left, they work so far ahead that it was going to take time for the cracks to begin to show.
This February the company also had an extra day thanks to the leap year, and they still didn't hit it. While AMD released a "Pre-Certified" version of the driver earlier in the month, which they say is exactly the same; it just doesn't have the Windows logo. The bottom line is they've prided themselves that for some odd 7 years they've offered a WHQL driver every month.
Del med dine venner