Jaikoz 8.x not matching recordings with the same acoustic Id in MusicBrainz. I tested it this way:
There is a release in MB, which I submitted a time ago. Now I submitted the same release to MusicBrainz again (with acoustid columne filled and with MBreleaseId and MBrecordingId columns empty).
Going to the Recordings page in MusicBrainz only gives me "add a new recording" for every track.
Because I submitted exactly the same tracks, with the same acoustids, there should be a match with the recordings, which already exists in MB.