Self grenade death at round start.

I often throw my nades down at rounds end in Alaska and shoot at them. Often directly underneath myself. I did this last game and at round start it blew me up. This has never happened before, must be something strange with the patch. I'll try my hardest to refrain from doing it for the forseeable future.

It happens right at the start of round 6, I believe.
Here's the game replay: http://www.mediafire.com/?tithhr2mgny