2 deaths in one sequence

[Sarge]

I'm noticing that a few times when I have been killed it's showing up twice in the message box that I've been killed by the same player

e.g.
Joe killed Sarge
Joe killed Sarge

Is this an error/bug (only counting towards one death) or are two deaths actually occurring at the same time? If the latter is the case, what causes it and how can it be avoided?

ta

Sarge