Mansell was leading in the latter stages of the Sprint race in Austria before falling to third at the chequered flag.
The Australian had scythed his way into the lead after shadowing race leader Nikola Tsolov throughout the opening half of the 21-lap encounter.
With three DRS zones around the Red Bull Ring, Mansell was unable to spring clear of Tsolov or Martinius Stenshorne in second and third.
The trio circulated in close proximity when, behind them, Sebastian Montoya crashed out at Turn 4 while battling with Alex Dunne for fourth.
It was a hefty crash that quickly drew the yellow flags and Safety Car.
As the yellow flags were shown, race leader Mansell lifted the throttle, while rivals Tsolov and Stenshorne remained full throttle, passing them moments before the Safety Car boards were shown.
“I had a been and responded to it out of intuition,” Mansell confessed.
“Obviously the other guys kept it flay, which in theory is what you should do, should wait until you get the VSC on the steering wheel, but just jumped a bit too early.”
In the car, drivers receive an audible beep to warn them that yellow flags are out.
However, it does not necessarily mean the drivers are in a yellow flag zone.
That was the case for Mansell, with Tsolov and Stenshorne within their rights to pass the Novocastrian.
“They didn’t pass under yellow, no, I just reacted to a beep that goes on radio,” Mansell clarified.
“There’s two beeps you have warning and then another one to confirm the VSC but just out of habit, when it came on, I just reacted to the first one on accident.”
Mansell wasn’t alone in his confusion, with Tsolov also admitted he was initially perplexed by the beep.
“I heard to boop and I saw Christian lifting off, and then I thought to myself ‘is there actually a Safety Car so quick, you know, without any other flags before that,’ Tsolov queried.
“I saw the panel immediately, that it was not Safety Car or anything, so I floored it, managed to get by Christian, and I saw Martin [Stenshorne] was in the inside.
“I knew there was definitely going to be soon a Safety Car or something so I broke late into [Turn] 6 and managed to keep the lead just in time.”
It was a decisive move as, with just a single lap of racing following the Safety Car’s withdrawal before the chequered flag, Tsolov held on to win from Stenshorne with Mansell a frustrating third.
The 19-year-old now sits sixth in the Formula 3 Championship heading into the Feature race in Austria, which begins at 08:30 local time (16:30 AEST) today.