Not sure if you’ve fixed anything, but right now this issue isn’t happening. I’ve written a twitter app that does nothing but prove the existence (or not) of this bug…
It opens a userstream connection, then sends 25 tweets and makes sure those tweets appear in the feed.
So either you’ve fixed it, or this only happens at certain times, and isn’t a consistent thing. I’ll keep an eye on it, and if i notice it happening again I’ll drop you a tweet with a link to my app that shows you all the IDs. 