retag creates different MusicBrainz URL than rip

[tlc]

A CD I've ripped left this in the log:

Album: Unknown Artist - Unknown Title

CDDB disc id:           5908ea07
MusicBrainz disc id:    uVZnV998NjLWu6GbQkV7tT3.Quk-
MusicBrainz lookup URL: http://mm.musicbrainz.org/bare/cdlookup.html?toc=1+7+171307+187+26555+49607+83322+108280+127277+147667&tracks=7&id=uVZnV998NjLWu6GbQkV7tT3.Quk-

My script log shows that it missed due to a network error.

MusicBrainz disc id uVZnV998NjLWu6GbQkV7tT3.Quk-
MusicBrainz lookup URL http://mm.musicbrainz.org/bare/cdlookup.html?toc=1+7+171307+187+26555+49607+83322+108280+127277+147667&tracks=7&id=uVZnV998NjLWu6GbQkV7tT3.Quk-
Disc duration: 00:38:01.600, 7 audio tracks
Warning: network error: NetworkError()
Error: NetworkError()
Continuing without metadata    
Submit this disc to MusicBrainz at the above URL.

When I try to use 'rip image retag *cue', I get a different MusicBrainz url that misses.

DEBUG [19676]                                  default           Dec 30 21:24:58      MusicBrainz submit url: 'http://mm.musicbrainz.org/bare/cdlookup.html?toc=1+7+171270+150+26518+49570+83285+108243+127240+147630&tracks=7&id=95ws_0UvRsVCeA06HXIH.dg59Y8-' (morituri/common/program.py:326)
DEBUG [19676]                                  musicbrainz       Dec 30 21:24:58      looking up results for discid '95ws_0UvRsVCeA06HXIH.dg59Y8-' (morituri/common/mbngs.py:265)
Error: NotFoundException(ResponseError(),)
Continuing without metadata
Submit this disc to MusicBrainz at the above URL.

Not in MusicBrainz database, skipping
DEBUG [19676] "retag"                          retag             Dec 30 21:24:59      done ok, returned None (morituri/extern/command/command.py:364)

Note that the offsets all differ from those in the original URL by 37 and a different id is calculated. This is a cue with a Hidden Track One Audio file, if it matters.

Cue:

REM DISCID 5908EA07
REM COMMENT "Morituri"
CATALOG 0000000000000
FILE "00. Unknown Artist - Hidden Track One Audio.flac" WAVE
  TRACK 01 AUDIO
    INDEX 00 00:00:00
FILE "01. Unknown Artist - Unknown Track 1.flac" WAVE
    INDEX 01 00:00:00
  TRACK 02 AUDIO
    INDEX 00 05:49:71
FILE "02. Unknown Artist - Unknown Track 2.flac" WAVE
    INDEX 01 00:00:00
  TRACK 03 AUDIO
    INDEX 00 05:06:02
FILE "03. Unknown Artist - Unknown Track 3.flac" WAVE
    INDEX 01 00:00:00
  TRACK 04 AUDIO
    INDEX 00 07:28:18
FILE "04. Unknown Artist - Unknown Track 4.flac" WAVE
    INDEX 01 00:00:00
  TRACK 05 AUDIO
    INDEX 00 05:30:63
FILE "05. Unknown Artist - Unknown Track 5.flac" WAVE
    INDEX 01 00:00:00
  TRACK 06 AUDIO
    INDEX 00 04:10:72
FILE "06. Unknown Artist - Unknown Track 6.flac" WAVE
    INDEX 01 00:00:00
  TRACK 07 AUDIO
    INDEX 00 04:29:70
FILE "07. Unknown Artist - Unknown Track 7.flac" WAVE
    INDEX 01 00:00:00