No, but it could have been without them knowing it. Just because an exploit hasn't been found and publicized by a security firm, doesn't mean black hats couldn't have found the bug and been using it without it being widely known.
That creates a near-constant stream of updates which is difficult for users & sysadmins to manage, and is why Microsoft and others have a "Patch Tuesday".
(I know that Oracle didn't do that here, but that's what the GP post was talking about)
If the sysadmins know when the patches are coming out then they can schedule downtime in advance and get things patched very soon after they're released.