Go to the recordings tab and try to change the recording of the first track. Search for "還有什麼可以送給你", expecting to find <http://musicbrainz.org/recording/adf8b0a1-0322-46c2-b4ea-60e4f444e745>. No recordings are found.
I've also seen this a lot while editing Japanese stuff, but for me, the direct search normally works (it doesn't seem to for your example here).
An example where the indexed search fails but the direct search works is http://musicbrainz.org/release/0385f276-5f4f-4c81-a7a4-6bd7b8d85a7e/edit (use the current track/recording name)
I notice that my example is the same example I mentioned on MBS-2111 which is marked as fixed. Perhaps you'd like to retest your example from that ticket too. It looks like your other ticket MBS-2184 which is marked as fixed no longer works either.
Yep, neither 戀愛令人心痛 (MBS-2111) nor 夜曲 (MBS-2184) work for me with the inline search, but both do if I switch to direct search. Should I reopen those two bugs?
I asked on IRC and Kuno's suggestion was to leave them closed and add related ticket links, so I'll do that.
This is odd, if I edit http://musicbrainz.org/release/1bc028c8-de6c-4bd3-9f86-161af4b6169e/edit and search for "還有什麼可以送給你" it still doesn't find anything with the indexed search, but does with the direct search. Is the search context-sensitive in some way?
My MBS-4979 branch doesn't have this problem (though live does), so I imagine it fixes it.
I can confirm that all the titles I mentioned now work on beta.musicbrainz.org