How does the foreign exchange loss mechanism work for loans to the Vietnamese subsidiary?

Our company provides U.S. dollar-denominated loans to our Vietnamese subsidiary. When the yen appreciates against the U.S. dollar, the yen-equivalent value of those dollar-denominated receivables decreases, resulting in a foreign exchange loss. In addition, because the funds are converted into Vietnamese dong for local operations, a depreciation of the dong against the dollar increases the amount of dong required for repayment, which also results in a foreign exchange loss. In both cases, the losses arise from exchange rate fluctuations affecting the value of the U.S. dollar.