Setting http://bugs.mysql.com/bug.php?id=76927 as the upstream bug, because the currently linked bug #69979 was discussing phantom duplicate values in REPEATABLE READ and was closed as Not a Bug.
Bug #76927 is about real duplicate values with the READ COMMITTED isolation level and/or innodb_unsafe_locks_for_binlog=1.
Setting http:// bugs.mysql. com/bug. php?id= 76927 as the upstream bug, because the currently linked bug #69979 was discussing phantom duplicate values in REPEATABLE READ and was closed as Not a Bug.
Bug #76927 is about real duplicate values with the READ COMMITTED isolation level and/or innodb_ unsafe_ locks_for_ binlog= 1.