In the "other" phase, that node appears properly. Remember they added TERRAIN PHASING in Cataclysm, too.
Unless it were for their amusement it seems that this would be quite a queer way to catch botters when they can do so from other more convenient venues.
For does saying herbs/mines disappear right when they try to loot them, you should be aware of the fact that some botters use hacks to farm from underground, wich is a much faster way to farm and of course you won't be able to see him looting your mine/herb. So thats no bug/issue as some of you might think.
The flying herbs have been present since like the beggining of time . I saw a mageroyal in the Barrens back in the day. It was in the air but I could reach it and harvest it. I saw alot of herbs like this during my playtime. On the other hand phasing is another story, a new one since Cata release and maybe it was present in WOTLK as well. Also underground farmers also make nodes magically dissapear...sooo nothing new so far only old bugs and bots .
When you use the first time any profile, make sure you babysit on it for at least 15-20 minutes to make sure things like this don't happen. If that herb is bugged, no one can catch it and your bot doing his circuit will pass on it and will try to grab it. Just blacklist! Another thing, Herbs/Mines disappearing in front of you, it can be another botters using that hack to run really quick and underground, just catching herbs. Make sure when you see that, to pop your nameplates and you'll see it.
They have been doing that for long, fx blizz places mobs inside tree's to make our bots stuck... its not a bug..
yeah, found an obsidium node in the middle of a tree this morning (used nocollison to get to it, but then changed my mind and left it alone..) Also, i've seen looots of bugged NPC's in hyjal.. damn you blizzard!