NBCOlympics
The push bar on the Russian sled piloted by Nadezhda Sergeeva didn't retract back into the sled after the initial push. For a few seconds the sled was flying down the track with the bar sticking out.
Luckily, they were traveling at a slow speed and only had to go around one turn, so it didn't do any damage to the track or the athletes.
Here's the sequence...
The start:
NBCOlympics
All was going according to plan:
NBCOlympics
This is when the bar is supposed to fall back into the sled:
NBCOlympics
Instead it got stuck:
NBCOlympics
The first turn. The bar scratches the top of the wall:
NBCOlympics
It was stuck for seven seconds:
NBCOlympics
Finally it fixed itself before it could do much harm, but the team finished with one of the worst times in the heat:
NBCOlympics