And the bolt was torqued to what ? From what I see, a loose bolt with no grease has grip and will roll back or forward, and a loose bolt with grease will slip back to where it rested !! The first bolt does not appear to be under a load !!
It is not torqued to anything in either case. The tension rod is unscrewed so it is about 1/16" above the washer in both cases. It is the same exact rod and is positioned so it is not touching the sides of the hole in the rim. The only difference is that when the threads have grease on them, the viscosity of the grease prevents the rod from turning from the vibration.
from Wikipedia about grease:
"Grease-lubricated bearings have greater frictional characteristics due to their high viscosity."