Can we get the original object so we can see what was going on?  Please?

I've seen this problem several times in Poser when you have an object with a lot of tris lined up.  Booleans often end up putting such things in the mesh and Poser hates them.  So, in some freebies I worked on I had to work around this exact same problem of strange artifact shadows caused by boolean-generated mesh.  I ended up ripping out the booleans and using another technique that resulted in a perfectly clean mesh.  BUT, I sure would have liked to have seen what was causing the problem and how to fix it without having to split verts, if at all possible.

Somewhat O.T. Note: I played around with bagginsbill's cylinder and found some interesting stuff.  I had a scaling problem exporting from an application once and decided to mess around with it while I had a cylinder guarranteed not to be generated in the suspect application.  It's slightly offtopic but, someone may get a kick out of it.

Load up the cylinder (P7 here) and use the default lighting.  Now, shrink the cylinder down to 1% scale and render.  To me, it's completely black and the shadows are all wonky.  However, the shadows work appropriately if you switch from depth-mapped to raytraced.  But, the cylinder is still black.

So,  I fiddled with the standard lights, just mucking around with the general settings and had no results - the cylinder was still black.   But, if I changed the default infinite lights from infinite to spotlight, walla! there's the cylinder's surface.

Here's the first series showing the scales and rendering options:

But, with my own default lights I prefer to work with for quick, preview renders:

So, infinite lights and depthmapped shadows don't like bagginsbill's cylinder shrunked down to 1%.  But, spotlights do. :) Turning off the IBL has no effect btw, the shadows/lighting weirdness will still be there for the infinite light.  I cranked up the shadows on the infinite to see what would happen but, there is a definite artifact still there if you don't.  Here, the shadow starts "inside" the cylinder at the above infinite light settings.

Weird.  Maybe some Node-Wizard, intimate with the ways of lighting and rendering can explain this one?