Steps to reproduce:

• Open http://musicbrainz.org/search/edits
• Add "Type" as a condition and select, say, "Edit artist"
• Add "Type" as a condition. Change it to "Status" and select, say, "Open"
• Search

The results page will only show results for type: "Edit artist", the status filter has vanished. I presume this is something to do with initially adding the same filter twice.