Expenses included in valuation amount adding with Stock received but not billed amount

Hello,
I am received goods for rs-50000/- and add freight(Expense included in valuation account) 1200/- in purchase receipt tax & charges with “valuation & Totals”.
Some time in GL posting “Stock Received But Not Billed” account including the amount of “Expense included in valuation” account-
Example:
Warehouse A/C Dr 50,000
Stock Received But not Billed 51,200
But sometime it is separate like-
Warehouse A/C Dr 50,000
Stock Received But not Billed 50,000
Freight(Expense Included in Valuation) 1200

But from Purchase Invoices, GL posting are always separate.
That would be great help if anyone can clarify the reason or where I am doing wrong. because of that my Stock received but not billed account is not nullifies.

Thank you.