Best thing to do is look at chart tracker to see if any transactions are flowing through that gl account that are not from the inventory subledger.
Then, check the inventory wip reconciliation report for that gl account to see if there are any transaction types coming through that are not ins…ins-stk,pur-ins, etc.
Then, check those transaction types in the inventory wip reconciliation report to see if any ins transactions are hitting accounts other than this one.
That will at least tell you that you gl controls are good, or if anybody is hitting that accounting directly through a different subledger. If that all checks out, next would be costing review.
If everything is setup correctly, that report should tie out every month, with the exception of possible rounding erros.