Not sure if this is a glitch in the game or in the GSU simulation:
In Stunt Race FX, during the first bonus race (between Novice tracks 2 and 3), I got the big-rig lodged in the course's edge and the game briefly froze.
There were only 2 seconds left on the timer when I did so, but the timer froze upon getting stuck, and controls became unresponsive. After maybe 10 seconds, the truck finally popped back out, and the bonus round ended.
ETA:
And now a similar glitch on Novice track 4. Though I didn't hit a wall, it's a similar freeze: the graphics are locked, with the exception of my wheels are still spinning. The checkpoint count-down timer is frozen, but the elapsed-time count-up timer is still going.
Background music continues to play, as well as the tire-squeal SFX. And as I type this I notice that there's also an engine-noise SFX that slowly increases in pitch/volume before peaking and resetting back to zero.
Pressing Y causes the BOOST meter to color cycle as if it's in use, but the meter never depletes. And of course, as I'm frozen, the car doesn't boost.