She tripped over the sheriff’s corpse, she placed the badge on the sheriff to honor him and a minor consequence of that is that the VR simulation can’t account for that so it slightly glitches.

The clue is that they’ve been using shitty tape to ensure all the cleaners will succumb to the toxic air within a few minutes.
Walk however arranged that the Supply department would deliver the better tape from Mechanical, this went unnoticed because they look very similar and ensured Jules would be able to survive.