2 Interesting Blog Commenting Problems!!!!

I am facing 2 different types of blog commenting problems that I personally never thought before. I am not a big lover of blog commenting method but this time just trying to get some comment backlinks and see what happens after Penguin update. However want to share the problems and see if anyone knows anything about it.

1- After commenting on a page when I check page source I don't see any backlink to my website or even any keyword which I just used as anchor text.

Yes I logged out from the site and checked in different browser to see whether the backlink is showing after logging out or not. Its showing! But not showing in page sources!!!

2- Another problem is in some cases I see different results for the real page and google cache page. I use SEO quake and SEO 4 Firefox of SEO Book to check whether the backlink is dofollow or nofollow. After commenting I see the backlinks are dofollow. But when I check in google cache I see the backinks are nowfollow!!!

Actually what are the answers of these questions????

Yukon, Mike Anthony, Mike Friedman, Backlinko, Paul, Nick0, wolfme let me know if anyone really know the answers.