<tl;dr> This is wrong / corrupted data in Wikimedia Git. There is no issue in Grimoire code.
We now know that this is about <100 commits (neglectable), about 1 repository, and about commits in Sep-Oct 2012 only (ancient).
Finding out how to rewrite Git history or workarounds (=blacklisting) in Grimoire do not feel justified.
Hence declining.

Longer version:

136155e528cf630d61a8352ab1a80ae2ddbc7a03: [[ https://wikimedia.biterg.io:443/goto/36fd5f31c8492209b2f3b4b8409eabba | Two commits in the mediawiki-config repo, on 2012-10-04 and 2012-10-24 ]]:

$:acko\> git remote show origin
* remote origin
  Fetch URL: ssh://aklapper@gerrit.wikimedia.org:29418/operations/mediawiki-config.git
$:acko\> git show b3a9d943c8084116ab7c49603419fa3b54919f32
commit b3a9d943c8084116ab7c49603419fa3b54919f32
Author: Leslie Carr <ttijhof@...>
Date:   Wed Oct 24 17:20:12 2012 +0000

    41355
    
    Change-Id: Ifb6f545ca9ffad988aa057f8db7bbc34b82ca728
$:acko\> git show 9ccdd75cef19b0fa205ab5c1e8685c1c24505119
commit 9ccdd75cef19b0fa205ab5c1e8685c1c24505119
Author: Leslie Carr <ttijhof@...>
Date:   Thu Oct 4 21:24:39 2012 +0000

    fixing account creation (grrr UTC time !)
    
    Change-Id: Ibfb33023474d7bc4f06af58d04c7c4fffaaac49f

d3af6e4d2efc077a6efa26aa0b3c9511504d18a8: [[ https://wikimedia.biterg.io:443/goto/1d4b88f188ab247a2755d8e973bfe4fa | One commit in the mediawiki-config repo, on 2012-10-29 ]]:

$:acko\> git show beb4da02c3abbbbf03b03284f77ba5ba72ebd1c9
commit beb4da02c3abbbbf03b03284f77ba5ba72ebd1c9
Author: Mark Bergsma <ttijhof@...>
Date:   Mon Oct 29 16:30:04 2012 +0000

    Add new bits servers
    
    Change-Id: Ife2fffaddccad9fde727f6d8c2ee20a2ea6e06d1

e891edbbfc7a9f3f7b2027cfb9de44e35d16cfb9: [[ https://wikimedia.biterg.io:443/goto/557be3e7260df169bf8132f6e75bf241 | Same mediawiki-config repo, one commit on 2012-10-29 ]].
3f893381f154b7a05b4c1271cdc413c3291e15f0: [[ https://wikimedia.biterg.io:443/goto/935aa2a3926e2a06ebfcdfe68512d3ff | Same mediawiki-config repo, one commit on 2012-10-09 ]].
4db496181f424e564fb692aadaab97fdbec793f9: [[ https://wikimedia.biterg.io:443/goto/d15454467641c935da51de250d4ecefa | Same mediawiki-config repo, 86 commits between 2012-09-27 and 2012-10-31 ]].
a8f40dc4f3f4f6f7e15ce6c604e3f96ede41976d: [[ https://wikimedia.biterg.io:443/goto/fa809d6516d4eecee141d55ab56c6360 | Same mediawiki-config repo, 2 commits on 2012-10-09 and 2012-10-30 ]].

I'm going to keep those specific identities (name vs other email address) whitelisted in the database and won't revert my commit as the problem looks neglectable when it comes to number of affected commits (<100), affected repositories (1), time (2012).