I just checked and Soft Shadows for the lights is turned off. For funsies I tried turning both Lit Fog and Soft Shadows on independently but my results remained concurrent. Random light shrapnel. I also copied the fixtures and stadium objects to a new document and had the same issue. So it's not a problem with the document or rendering settings. I'm rather new to Vectorworks and not sure even how to begin troubleshooting this issue.