Supplier Credit with tax included resulting wrong Inventory Valuation

It seams that there is a problem when entering Supplier Credit not, if the supplier has Tax included in the prices.
Example:
Enter a supplier invoice (for a new product) who has tax included in the price, in stock_moves table price and standard_cost gets registered at the same price, both without TAX
Enter a supplier credit note for the above product (same price with tax, same supplier), the in stock_moves table price gets registered WITH TAX included, and standard_cost gets registered without TAX (it dose not change)

So as a result, the standard cost for the item will be ok, but the Inventory Valuation for the item will not be correct