I don't know if this is a skin issue or a XBMC issue. But when I have watched all episodes of a tv-series it reports that I have one left unwatched. Even though I can click into the season and see that all episodes have the "watched" icon besides them.
I run XBMC Windows SVN build 16402
I get that randomly as well on some TV Shows. I have concluded that there are no hidden files in the directory that could cause it to show this way. I've even marked everything as watched and yet, it still says I have 1 (or 2) unwatched. I've seen this issue since before Atlantis was available.
try disabling stacking of tvshows and see if that makes a difference
It didn't :/
And it is quite random. Some shows gets 0 when all eps are watched, but the most ends up with a 1.
I got this as well for one of my shows, but when I investigated further I noticed that I got two files for the same episode. Xbmc seems get a bit confused from this.