After a bit more digging, I tend to think that Auctioneer is, in fact, the problem. If I disable it, things are displayed as they should be in the AH, re-enable it, and it's right back to searching indefinitely. Unfortunately, at least in my case, closing the panel and reopening it does not alleviate this issue. So, I suppose I'll just have to do without that particular addon until such time as it gets updated and/or fixed. I'd much rather do without it than nUI.
I may try removing it completely, and reinstalling it, chances are that I simply installed the updated versioins over my original installation, and that can be the source of problematic behavior at times.
The rep bar thing isn't a major problem by any means, and the rest of the nUI features more than make up for that mild annoyance.
Edit: Just spent some time browsing the Auctioneer site, and according to their forums, there are problems with the addon at present, including indefinite searching. They offer a few workarounds for these problems there as well for those interested. (
http://auctioneeraddon.com)