This is an issue two of our clients have encountered : the item avaibility in the result page does not match the one in the detail page. e.g.: The items have a notforloan value of -2, which is mapped through Authorised_Values to "In Processing" (or equivalent) but on the OPAC result page, it is displayed as "On Order". The detailed page show the correct value. From my analysis, this is because whereas the intranet results and the opac details use the database to get items statuses, the opac result goes through the XSLT processing, and doesn't have access to the Authorised_Values table. This is worked around by some hardcoded values in the "item namespace" created by XSLT.pm. It's possible to fix this issue case-by-case for each client, but that's a very ugly solution. I don't plan to submit a patch to this bug, because I am not sure how to solve the issue. (If my explanations are unclear please tell me)
The result page groups the different values, lost, not-for-loan (negative values = on order, positive = reference). Fixing this to show the value from the authorised values has been discussed on a different bug (can't locate it right now)
*** This bug has been marked as a duplicate of bug 7611 ***