Sorting by podcast everything is fine, the podcasts are sorted and grouped as expected. Episodes of each particular podcast is sorted by title.

I want them in date order not title order, so I hold down Ctrl and click the date heading.
The expected behaviour is that the podcasts would now be grouped and sorted by Podcast and then sorted by date.
What actually happens is shown below.

Is anyone else seeing this? I don't see this behaviour in any other node (though I've only checked quickly).
MM4.0.0.1378 (Installed in Portable mode)
Win7 x64
stan9980