The stack of 3 piles appearing directly behind the skylights likely has a concentrated weight of approximately 1750 lbs distributed over 3 truss sections. I would claim this is too much weight as the (best practices) rule is in our area is to never exceed 6 per stack. A truss connector plate slipping or even a truss cracking with that load may be the problem. Add a roofer or two walking around the stacked piles and you can expect to have another 300 to 400 lbs stressing those sections. A mathematical equation assesses the maximum structural load on truss sections based on materials used, span and slope as it does on truss connector plates where a “shear load” is established.
The responsibility might very well be directly with the entity contracted to load the roof.
Good luck, and as Darkthirty suggested, document everything.