WordPress RSS Feeds Crossing in Google Reader

I’ve been having a problem with two WordPress installations crossing RSS feeds. By “crossing”, I mean that my wife’s items are showing up in my feed on Google Reader. However, when you look at the RSS directly, there doesn’t seem to be any crossing of posts. My RSS
source only has my posts and her RSS source only has her posts. This indicates to me that the problem isn’t on my server. (Otherwise, the RSS source itself would show the crossed posts.) Google, however, insists that it is a problem on my server.

The only thing I can think of is that both of our blogs are on the same shared hosting account (though at different URLs) and thus on the same IP Address. Could this be causing entries from one feed to show up under a different feed? Has anyone else had this happen? How do I stop it from happening? (My wife likes to keep her identity as anonymous as possible and having her entries show up in my blog doesn’t help.)