Rubbish. It's not a feature, it's not a test, it's not by design. It's a bug.
It happens on one map and neither the map maker (Fester) nor HTC have figured out why, or if they have they haven't said. However, since HTC is working solidly on the update I doubt there's been a huge in depth investigation to solve a bug that will be gone with the new version anyway.
It's not a massive deal, nowhere near as big a deal as having no dar bar at all and cons appearing at 20,000ft.....which is another bug that hasn't been fixed cos it'll probably be gone with the new version as well. Fixing bugs that aren't game destroying is not a priority when there's a brand new version being developed.