The volume (under 1mm) is not that huge. Just seems to indicate the selling volume is greater than the buying, not by much. I don't have level 2, so I can't judge. If someone can post the L2 history today maybe we can understand it better (i.e are the sells in large blocks, is it always the same broker, etc.).
Meantime, chin up, everything still looks hunky-dory, IMO.