Publications do not normally have "NonGenre" as one of their options for "Pub Types". This can cause serious problems with NonGenre titles to come disconnected from their publications. For example, <a href="http://www.isfdb.org/cgi-bin/title.cgi?1444273">this title</a> is a non-genre title whose only publication thinks it is a Non-Fiction book. So the title links to the pub, but the pub cannot link back to the title. You can't change the publication type to match with the title type. Everything I've tried (e.g. unmerge the one pub from the title; change the title to NONFICTION so it matches, then try to change things back to NONGENRE) fails to get this pub/title to connect to each other. I've even unmerged the pub, then gone to the empty title and done "Add publication to this title" to copy the data back in. It forces the new publication to be of type "NOVEL" (alphabetically, the next choice after "NONGENRE").
Anonymous
As per Wiki discussion, only Title records (but not Publication records) can be NONGENRE at this time. In addition, only novels can be NONGENRE. We plan to change it in the future so that any title types could be NONGENRE.