It happens all the time with QB rushing yards props.
A few years ago I had Mahomes I believe over 29.5 rush yards and he was at 40 or so in the final 2 minutes of a 'victory formation' win... no problem.. 3 knees is -3 yards, still a comfortable win.
Wait though! Instead of taking normal knees to end the game, he bizarrely shuffled backwards 3-5 yards each time before taking the knee (I suppose it was running additional seconds off the clock, but it was completely unnecessary due to the defense having long given up)... he ended up losing 12-15 yards in total and finished with 25-28 rush yards. I honestly don't remember the specific total, but it was enough to cost me the wager.
I couldn't even be mad about it, it was so ridiculous.
EDIT: And to be clear, it wasn't a "IT'S RIGGGGGGGGGED!" thing. There was a legitimate explanation for it... he had to burn a few more seconds than 'normal' knees would have generated... the way he did it looked so bizarre though because the defense wasn't even attempting to put a rush on him. 
(this is why you don't ever bet more than you're comfortable losing... and why it should be viewed as entertainment)