Ok, I downloaded your file but I only had time to give it a quick look. I didn't see much wrong with your rig at first glance, aside from a strange placement of the elbow poles in the armature, but that wouldn't cause the issues. I'll have to give it a better look when I have some time, but nothing jumps out at me.

I will say though that you do have some other geometry in the scene that could give you trouble when rendering. You have a lot of Z-fighting on the ground planes, and that park bench has a few inverted normals at the bottom. The ground plane in particular might give you some artifacts or flicker in areas where the polygons are overlapping.

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