In the tutorial you can actually clean up a signal more than 3 times, resulting in the light of the disk to turn off. Haven't gotten to the stage in the game where I could do that myself yet, so I don't know how the disc would behave when turned in. Discs can be emptied without problems however, and they act like normal.
There's also a deep hole on the sand bank that will cause an ATV to get stuck there with no way to retrieve it. Resetting the vehicle will not work, as the vehicle will still stay at that position.
Probably not fixable due to physics, but when you push down a glowstick hard enough into the ground it will lock onto the surface but vibrate violently, causing it to be difficult to grab again. Tested on the ramp to the garage.