1) Go to https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=202143
2) set blocker flag == '?'
3) add a private comment
4) click "save changes"

DBD::Pg::st execute failed: ERROR:  duplicate key violates unique constraint
"flags_pkey"
 [for Statement "INSERT INTO flags ( type_id, 
                                    bug_id, attach_id, 
                                    requestee_id, setter_id, status, 
                                    creation_date, modification_date)
                VALUES (24, 
                        202143, 
                        NULL,
                        NULL,
                        141215,
                        '?', 
                        '2006-08-11 08:13:02.497196-04',
                        '2006-08-11 08:13:02.497196-04')"] at Bugzilla/DB.pm line 71
	Bugzilla::DB::SendSQL('INSERT INTO flags ( type_id, \x{a}                     
         ...') called at Bugzilla/Flag.pm line 489
	Bugzilla::Flag::create('HASH(0x1819ad0)', '\'2006-08-11 08:13:02.497196-04\'')
called at Bugzilla/Flag.pm line 409
	Bugzilla::Flag::process('HASH(0x1819930)', '2006-08-11 08:13:02.497196-04',
'Bugzilla::CGI=HASH(0x154d9f0)') called at
/var/www/html/bugzilla/process_bug.cgi line 2294