I have upper 2.65 lower 10%ati 1000cc injectors. First I thought it was a broken belt( it was shredded) the we looked closer the tensioner was broken and the damper moved as well replaced the tensioner and one pull it broke again and my power steering pump seized and again it’s my black belt not green
You said the Damper moved? Is your crank pinned?
If it's not, I almost guarantee that you spun the hub on the crank and it backed out. This would either,
1) Spin the crank on the hub and it would walk the belt off and shred it.
2) Stop the belt completely and the inertia of the sudden stop would shred it.
If not that then, did you install the spacer on the pensioner for the accessory belt?