I have noticed that if I have two albums with different names but the exact same "sort as" under the "album" field in the Sorting tab, that one of the two albums will not appear in the Column Browser. For example, let's say I have one called Album A and another called Album B. If get info on a group of Album A songs and go to the Sorting tab, let's say it shows album = "Album A" and under that sort as = "Album 1". Now if I get info on a group of Album B songs and go to the Sorting tab, let's say it shows album = "Album B" and under that sort as = "Album 1". If that happens. Album B will not appear in the Album list in the column browser. But if I re-open the Album B songs and change sort as = "Album 2" (providing it's unique) then Album B will now appear.
In my opinion the sorting field should be used for sorting ONLY, but it doesn't appear to be designed that way - or else it's a bug. Based on the way the query works, it will lump two albums of different names under the SAME ALBUM NAME if the sort as field under album are not unique.