Before looking into deviations between PROBAL and GL account, try importing the product balances to the General Ledger again from the Product Balances folder in PAR using the context menu option:
 "Import Product balance to General ledger". 

The reason for the deviation could be that new transactions have occurred for this particular period after the last time the job was initiated. The deviation might disappear after this import job has been run. 

The Inventory Balance (IB) can be checked to make sure it has been imported and no entries have been created in the previous year that would trigger the need to import the inventory balance (IB) again.

If the deviation is still there after this import has been done, you need to investigate the deviation further.

More information regarding deviation handling can be found here: Deviation Handling