This is weird. There are no other calls to Curl::Multi.new that pass a feed that I can find and the source for curb specifies that it doesn't take any parameters. I've removed the feeds being passed in the specs and all tests now pass.
Only one attribute of a feed would get updated before the ||= shortcuts in FeedUtilities#update_from_feed. This meant, for example, that I wasn't getting etags updated because I wasn't setting the title attribute before calling update().
… why that was in carson's commit
… they don't conform to the standard.