Hi Eyal,

patch #81877 that solves it is ready and waiting for CR.
It looks like there was some changes in Bugzilla that returns the external tracker id number as string instead of int as it was previously.

@Former user did you have a chance to look into this issue?

I've seen this too.

Gerrit was updated recently as part of https://ovirt-jira.atlassian.net/browse/OVIRT-1450#icft=OVIRT-1450 so this might be related.
Looking at In logs on Gerrit I see the hook triggered successfully:

2017-09-01 09:25:33,718::16918::INFO::change-merged.bz.99.update_tracker
2017-09-01 09:25:30,646::16923:EBUG::ESC[94m----------------------------------------------ESC[0m
2017-09-01 09:25:30,646::16923:EBUG::ESC[96mSTART HOOK: change-merged.bz.99.update_trackerESC[0m
2017-09-01 09:25:30,647::16923:EBUG::ESC[94m----------------------------------------------ESC[0m
...
2017-09-01 09:25:30,874::16923:EBUG::==> bug_urls: [u'https://bugzilla.redhat.com/1445199']
2017-09-01 09:25:30,874::16923:EBUG::==> bug_ids: set([u'1445199'])

2017-09-01 09:25:30,874::16923:EBUG::==> updating tracker with bug_id: 1445199

2017-09-01 09:25:30,874::16923:EBUG::==> checking bug_id: 1445199
2017-09-01 09:25:31,952::16923:EBUG::==> classification: oVirt
2017-09-01 09:25:31,953::16923:EBUG::==> product: ovirt-engine
2017-09-01 09:25:33,699::16923:EBUG::ESC[94m--------------------------------------------ESC[0m
2017-09-01 09:25:33,699::16923:EBUG::ESC[96mEND HOOK: change-merged.bz.99.update_trackerESC[0m
2017-09-01 09:25:33,699::16923:EBUG::ESC[94m--------------------------------------------ESC[0m

2017-09-01 09:25:33,719::16918:EBUG::==> OUTPUT::
################################################################################
0
0

• Update Tracker::#1445199::OK, tracker status: MERGED
  ################################################################################

2017-09-01 09:25:33,719::16918::INFO::==> RESULT::{'msg': '* Update Tracker::#1445199::OK, tracker status: MERGED', 'code_review': 0, 'verified': 0}

The last line is also saved in gerrit UI, so something in Gerrit-Bugzilla integration is broken as the hook thinks the tracker was updated while in fact it wasn't