Hi Nico,
You're doing nothing wrong as far as I can tell.
I can't reproduce the issue where the wrong latest version is shown for an uncached package. Does it only happen for that one package? How many versions of it are on the external feed?
Regarding the other issue - that cached packages in the browse list may show the incorrect latest version - there is not much we can do about that. The browse list both in ProGet web interface and in the VS NuGet dialog sort by popularity and so frequently return totally different packages. The only way we could guarantee an accurate "latest version" display for cached packages on there would be to individually query those packages from the connector, which would drastically slow down the results. That said, I agree this isn't great. I'll chat with the rest of the team and see if we can come up with a better way to handle this.
-Greg
