Most likely is one of the ERP did not kick off the appropriate change pointer; or the CIF was temporary down\stuck. If you really want to verify, here's a workable approach
1) Check when is the last time the inventory for your batch is updated (Tcode CFG1; Note your Detail CIFLOG has to be turned on); and whether there's any issue with CIF update
2) On ERP side, see the transactional updates of your batch inventory (Tcode: MB03)
3) Cross match the 1 & 2; and you would probably get the answer
Cheers