Functional Amount in copied journal is not correct

Hi All
I have a journal from source Payable which the currency is foreign currency (USD).
Then I did autocopy this journal. But after review the copied journal, it seems the functional amount(THB) is not changed. It's showing the foreign currency in functional currency field.

Here is the example of journal

1. JV from Payable (currency = USD)
    Entered Amount          Accounted Amount
    3,407.3                         102,201.58
2. Copy journal
    Entered Amount           Accounted Amount
    3,407.3                         3,407.3

Please see the attahced file for the screenshot.

Please let me know if you experienced this issue? Where can I check for setup?

Thanks,
Ying