Anyone else have had this happen...?

Was killing the doppleganger, and just as I killed in he got a finishing hit back on me... Got me the bonus, but the mission is marked as failed...

What's your map look like?

Red skull with only the bonus sword through it.

Has this happened more times or only once? Have you tried the mission afterwards?
I just did the mission without any problem.

Well I guess it makes sense. You get the bonus by killing the Doppelganger in a certain time frame...but to finish the mission you actually have to beat him, not just kill him. If you kill somebody but they kill you too, you haven't beaten them. That's a draw.

Yeah, completed it without problem after it happened.

I guess that explanation makes sense. But it's still a rare thing to happen.=P

Ive had this happen before augury rock was marked with a mission icon, degen killed him then me, got the exp... just had to complete it again...

This is quite common, way back when it was used to ascend your character at level 1/2, by killing doppel and dying at same time you got 0 exp but still ascended, but that got fixed

So yeah it happens, gw be buggy yo'

Yes, you completed the bonus objective by beating him in a certain time, but failed the mission of SURVIVING against him.

... or am I the only person confused?

Yup - same here - you have to stay alive till the cut scene activates to get mission credit.

Do the mission and you can clearly see that the bonus triggers the instant you kill him, but it takes a few seconds for the cutscene to kick in and finish the mission itself.

Don't think it was actually intended by Anet that this be a possible outcome of the mission, its just an amusing side effect of how the mission is scripted.

I had something sorta similar happen to me with Unwaking Waters on my warrior when I first completed it back during the 1st week Factions was out. I successfully completed the mission, received the rewards for it and credit for it and could continue the story, BUT on the map the outpost was still an incomplete mission outpost. Stayed that way for the longest time (like 4 yrs i think) even after I redid it several times. Then after HM came out and I completed it on HM the outpost finally changed to the completed outpost.

Bonus and mission completion are not checked at the same time.

You get the bonus as soon as the doppelganger dies under the time limit.
But you get the mission after the game prepares the cinematic and check you as being alive.

That leaves a window of time in which a flying spear attack or other projectile sent by the doppelganger can hit you and kill you.

It happened to me once or twice.