Apply thread locker as necessary
If this problem persists, or if you want to nip it in the bud, you can apply thread locker to all eccentric nuts to prevent them from coming undone.
Manually turn all V-wheels, checking to make sure none are freely spinning
The V-Wheels shouldn't be so tight that you can't spin them, but they shoudn't be freely spinning at all.
Tip: position the eccentric nut then tighten the bolt.
Tip: If the eccentric nut is coming loose over time, consider adding thread locker.