I think I found a bug...
My suspicion is, the timing of mission complete, determining challenge success, then posting it to the popup accounts for that 1 second discrepancy. It's entirely possible the timer keeps on timing until the popup, instead of stopping when the mission completes.
Just my guess. If it is a bug it's a pretty trivial one but by all means report it.
"Null is as much an argument "for removing the cottage rule" as the moon being round is for buying tennis shoes." -Memphis Bill
Woah. Close call.
Goodbye. Not to the game, but the players. Goodbye. Everyone, remember to have fun. That's all I can say.

My other guess is the extra second is the time it took Hopkins to realize he was defeated. He's the most pathetic AV after all.
"Null is as much an argument "for removing the cottage rule" as the moon being round is for buying tennis shoes." -Memphis Bill
Well, it could have something to do with arcanatime.
You fell within the server tick before it realized you ran over.
BrandX Future Staff Fighter

The BrandX Collection
I figured it was a timing thing, just pretty odd to see it. We brought Hopkins down quickly and then I looked up at the timer and chatted "20 seconds!" We busted our collective butts to clear that huge room, but I thought for sure we failed.
Where to now?
Check out all my guides and fiction pieces on my blog.
The MFing Warshade | The Last Rule of Tanking | The Got Dam Mastermind
Everything Dark Armor | The Softcap
don'T attempt to read tHis mEssaGe, And believe Me, it is not a codE.
Head of TRICK, the all Trick Arrow and Traps SG
Part of the Repeat Offenders
Still waiting for his Official BackAlleyBrawler No-Prize

Both work well.
Just did a Manticore TF.
Set the challenge for a time limit of one hour.
We succeeded.
I'm not sure how.
Where to now?
Check out all my guides and fiction pieces on my blog.
The MFing Warshade | The Last Rule of Tanking | The Got Dam Mastermind
Everything Dark Armor | The Softcap
don'T attempt to read tHis mEssaGe, And believe Me, it is not a codE.