After a few months of people pointing the issue out, Microsoft has finally acknowledged that the 2011 dashboard update has created a problem with the console's video playback.
Xbox spokesman Larry Hryb has said the company is "aware of the colorspace issue" affecting "some Xbox video apps", and that Microsoft is "working on a fix".
Note he only seems to be addressing the issue of colours appearing "washed out", not the other allegations that third-party video apps are "no longer being rendered in native resolution".
"No ETA yet", Hryb adds, "but we hope to have an update soon".
@majornelson [Twitter, thanks Henry!]