When the document count posted to review does not match the number of documents processed there are a few steps to confirm the processing document counts.
In Process - Manage Collections review the Import for the data and confirm the exceptions.
When exceptions are reported click on the Exceptions tab to receive more detail about the exceptions.
Encrypted or password protected files may be placed in review but corrupted files or corrupted container files may need additional attention.
If ALL files from the data sent are needed for review the Review Policy will need to be modified. Go to Settings - Review Policy and change the policy to be Do not dedup and to include containers and binary files