Google Sitemaps & punishment for bad URLS?

[RUNNERagency]

Hoping y'all have some input here. This is along story, but I'll boil it down:

Site X bought the url of Site Y.  301 redirects were added to direct traffic (and help transfer linkjuice) from urls in Site X to relevant urls in Site Y, but 2 days before a "change of address" notice was submitted in Google Webmaster Tools, an auto-generating sitemap somehow applied urls from Site Y to the sitemap of Site X, so essentially the sitemap contained urls that were not the url of Site X.

Is there any documentation out there that Google would punish Site X for having essentially unrelated urls in its sitemap by downgrading organic search rankings because it may view that mistake as black hat (or otherwise evil) tactics?  I suspect this because the site continues to rank well organically in Yahoo & Bing, yet is nonexistent on Google suddenly.

Thoughts?

[Klarke]

I've never seen anything like that.  I don't think they punish or think its some kind of black hat shenanigans.

More likely, loss of traffic may have to do with 301 redirect ?