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Yeah, the 301 should be taking effect, but apparently Google thinks that the 301 is more of a 302. We have seen Bing come out and say sometimes they will ignore commands and treat a 301 like a 302. Do you 301 things often? Regardless, since there are no more links pointing to the /Lavender page, you can 404 or 410 that page and let it drop in the index. The new one should take it's place. You do risk losing traffic for a little time though, just be aware of that. Should fix the issue though.

I've asked the help team to come in and answer this one. If it's something beyond a known glitch, they'll likely ask you to start a thread over at the help desk.

I notice similar behavior in my campaigns. Comparing LRD here to the list at Google WMT, I find dozens of LRSs (even from domains I'm not familiar with) that don't show in my SEOmoz campaign reports or Open Site Explorer. I second the question and have even posted one of my own here: http://www.seomoz.org/q/linking-domain-dropped-followed-by-significant-decrease-in-domain-authority.