Oops, I Was Wrong: Lr5.2 Beta Does NOT Fix That Nasty Publish Bug )-:

Sigh, I spoke too quickly with my previous post....
the nasty Lr5 Publish bug is not fixed in the Lr5.2 beta.

I tested for this bug during the runup to 5.2 and though it was fixed,
so either it became broken again in the final 5.2 beta build that Adobe
released to the public, or, more likely, I just didn't test well enough.

In either case, the bug remains at least to some extent, so as per my initial post, those
working in Publish with Lightroom 5 are advised to make their selections with
the filmstrip instead of the grid, or you risk that your photo/metadata changes are
applied to a completely different set of photos than it appears.