For "tilt" reference - compare vertical angle of corner of plate to edges of nut.
For "tilt" reference - compare vertical angle of corner of plate to edges of nut.
Zoom with angle reference lines illustrating the tilt to this particular rock bolt. Investigations of other rock bolts in images show they are accurately vertical to the concrete surface.
IMO: I'm beginning to suspect they ran into unstable rock as this side of the spillway has shown known "seams" of rock that have easily caved away from the damaged end view of the upper spillway (before covered with mesh/shotcrete). They may have had to re-angle the drill to get a better anchor emplacement in rock.
Aligned angle point lines reveal a tilt angle to this particular emplaced rock bolt - angle is 3 degrees arc left from vertical. Suspect drilling ran into poor rock & re-drilled at a new angle.
I wonder if the bolt was installed slightly off angle. They might have been hurrying to get the last few in, and they were operating the drilling rig on a fairly steep slope towards the bottom of the spillway.
Something to watch for certain.