Hi Thierno,
As per SAP Note,1096330, the reason for the inconsistency is still not known.
However, SAP has given a workaround by giving a report which on execution removes the inconsistency.
Check SAP Note 865271. In the attachements, there is a file which contains the report provided by SAP. This has to be created in SAP system and on execution will solve the issue.
Hope it helps...
Thanks,
Amlan