This message: "An update for the Google Reader offline feature is available" appears way too often in Reader and with no noticeable changes. I think a little more info would be good. They don't even talk about this in the official Google Reader blog.

Does anyone know what's going on code-wise with these Reader updates?

This could be some browser specific; I never see it in Safari OSX 4.x. in daily use, it simply updates itself transparently. As web apps go, GR is pretty complex an instance of, and thus easy to tweak until known imperfections are ironed out, while new ones fused in ;-)). As for tour "little more info"... see http://www.phrases.org.uk/meanings/10400.html