green builds not visible in mixed series

In a given series, when at least one arch has either failed or is unpublished or has missing deps (...), getBuildSummariesForSourceIds() doesn't report anything about successful builds:

Compare this build: https://edge.launchpad.net/~ubuntu-mozilla-security/+archive/ppa/+sourcepub/1153380/+listing-archive-extra
(6 arches successful, 1 failed = sparc)

>>> builds = ppa.getBuildSummariesForSourceIds(source_ids = '1153380')
>>> builds
{u'1153380': {u'status': u'FAILEDTOBUILD', u'builds': [{u'can_be_retried': True, u'current_source_publication_link': u'https://api.launchpad.net/1.0/~ubuntu-mozilla-security/+archive/ppa/+sourcepub/1153380', u'can_be_rescored': False, u'build_log_url': u'https://launchpad.net/~ubuntu-mozilla-security/+archive/ppa/+build/1760876/+files/buildlog_ubuntu-hardy-sparc.firefox-3.0_3.6.4+build6+nobinonly-0ubuntu0.8.04.1_FAILEDTOBUILD.txt.gz', u'datebuilt': u'2010-05-28T19:18:12.463611+00:00', u'title': u'sparc build of firefox-3.0 3.6.4+build6+nobinonly-0ubuntu0.8.04.1 in ubuntu hardy RELEASE', u'distribution_link': u'https://api.launchpad.net/1.0/ubuntu', u'resource_type_link': u'https://api.launchpad.net/1.0/#build', u'buildstate': u'Failed to build', u'datecreated': u'2010-05-27T22:50:35.033198+00:00', u'pocket': u'Release', u'http_etag': u'"dd0a88d7ee5e385255529709a692d32de68cc03e-51923307cac4f64cea2d5909bf671b41661bf64b"', u'dependencies': u'', u'date_first_dispatched': u'2010-05-28T19:08:21.674930+00:00', u'self_link': u'https://api.launchpad.net/1.0/~ubuntu-mozilla-security/+archive/ppa/+build/1760876', u'arch_tag': u'sparc', u'archive_link': u'https://api.launchpad.net/1.0/~ubuntu-mozilla-security/+archive/ppa', u'upload_log_url': None}]}}
>>> pp.pprint(builds)
{u'1153380': {u'builds': [{u'arch_tag': u'sparc',
                           u'archive_link': u'https://api.launchpad.net/1.0/~ubuntu-mozilla-security/+archive/ppa',
                           u'build_log_url': u'https://launchpad.net/~ubuntu-mozilla-security/+archive/ppa/+build/1760876/+files/buildlog_ubuntu-hardy-sparc.firefox-3.0_3.6.4+build6+nobinonly-0ubuntu0.8.04.1_FAILEDTOBUILD.txt.gz',
                           u'buildstate': u'Failed to build',
                           u'can_be_rescored': False,
                           u'can_be_retried': True,
                           u'current_source_publication_link': u'https://api.launchpad.net/1.0/~ubuntu-mozilla-security/+archive/ppa/+sourcepub/1153380',
                           u'date_first_dispatched': u'2010-05-28T19:08:21.674930+00:00',
                           u'datebuilt': u'2010-05-28T19:18:12.463611+00:00',
                           u'datecreated': u'2010-05-27T22:50:35.033198+00:00',
                           u'dependencies': u'',
                           u'distribution_link': u'https://api.launchpad.net/1.0/ubuntu',
                           u'http_etag': u'"dd0a88d7ee5e385255529709a692d32de68cc03e-51923307cac4f64cea2d5909bf671b41661bf64b"',
                           u'pocket': u'Release',
                           u'resource_type_link': u'https://api.launchpad.net/1.0/#build',
                           u'self_link': u'https://api.launchpad.net/1.0/~ubuntu-mozilla-security/+archive/ppa/+build/1760876',
                           u'title': u'sparc build of firefox-3.0 3.6.4+build6+nobinonly-0ubuntu0.8.04.1 in ubuntu hardy RELEASE',
                           u'upload_log_url': None}],
              u'status': u'FAILEDTOBUILD'}}
>>>

only the sparc build is visible. nothing about the other 6 arches.