Video results end in black and white?

I’m using webpagetest’s awesome scripting functionality to have it only record the second page visited, so that I can verify the performance improvements of the Quicklink library. When viewing the saved video captured by webpagetest, I can see a brief visual of the initial page (which is in color), but then the page that webpagetest is logging/testing displays in black and white, and the video ends.

I’ve spent a bunch of time looking through the WPT documentation (as well as these forums!), but can’t see any reference as to why the videos end in black and white and what its significance is. Anyone have any ideas?

I’ve also tried exporting videos from the filmstrip view (which show the thumbnails in color), but when exported the videos always change the colors of the page being tested to black and white.

If this is a “feature, not a bug”, is there any way to disable this feature?