Scot Christie, who prefers the 1000m event, looked more relaxed before putting in a final burst which saw her edge Italy's Arianna Fontana in a photo-finish before she was penalised and placed in last position.
Within minutes of the finish of the heat it emerged that Christie had been penalised for an infringement at the finish line.
The 23-year-old from Livingston was devastated to be disqualified in the final of the 500m on Thursday for crashing into Fontana and was visibly upset after her second stroke of bad fortune.
Christie's result was initially flagged up as 'penalty' which was later changed to 'DNF' (did not finish).
GB short track coach Nicky Gooch, by way of explanation, said: "The referee has said Elise didn't cross the line.
"She has crossed inside the finish line and he has ruled that that is off-track.
"Therefore he is saying she hasn't finished the race.
"She (has) done nothing wrong in the race, tried to make sure she was nowhere near Arianna and get her on the line, but the referee has called off-track.
"It has been called before but not something that normally happens.
"I was shocked. I looked at the video and you are talking centimetres."
Fighting back tears, Christie said she had been the victim of threatening messages on social media following her first disqualification and has since deleted her Twitter account.
"I have had a few people threatening me," she said. "It's been a tough few days."
Speaking about today's disqualification, she said: "I'm gobsmacked. I expected the decision the other day but today I have no ideas what's going on.
"I'm finding it quite hard."