So an NBC News poll showing Udall with a comfy lead is totally plausible but a Quinnipiac poll showing Gardner with a similar lead is not? Sorry, but that doesn't make much sense to me.
Either way, Democrats here and elsewhere have pointed to Udall's consistent lead in the polls as evidence of the supposed "lean D" status of the race. In two days you have as many polls showing Gardner winning, one of which is well outside the margin. Is he up eight? Probably not. But he may very well be leading at this point, which is means that this race is far from Lean D.
The +6 might have been a stretch, but it was at least in the ballpark of other polls (the two before and after it was +4, +2, +3, +4). This poll is 7 points off from anything else out recently, 6 points off from anything out the entire cycle.
There have been polls showing Gardner up four and Gardner up two. Like I said, the point isn't that Gardner is up by eight. The point is that it doesn't make a lot of sense to infer from the data that
either candidate has much of a durable lead. The Lean-D proposition is hard to sustain when two polls in two days show the Democrat losing, especially when one of those margins is eight points.