SUMMARY
Using the "To Amount" currency conversion function for a foreign dividend transaction that has BOTH "Fees" and "Interest" values results in extraordinary exchange rates because the function uses the "Fees" value as the denominator of  the currency conversion rather than the "Net Transaction Value" (which is what the user is trying to target with the "To Amount" field).

STEPS TO REPRODUCE
1. Create a FOREIGN currency dividend transaction (may apply to others) with values for both "Fees" and "Interest"
2. Tab to the end of the transaction dialogue box - the net value may or may not be calculated
3. Press enter to post the transaction
3. When the Exchange to Base Currency dialogue appears select "To Amount" function

OBSERVED RESULT
The originating foreign amount as stipulated in the text of the dialogue box is only the "Fee" amount 

EXPECTED RESULT
The originating foreign amount should be the Net Transaction Value which can then be converted to a target value to avoid rounding / reconciliation problems.

N.B.
Using the alternative "Exchange rate / Price" function works correctly on the same transaction.

Using the "To Amount" function WITHOUT a "Fees" value (i.e. no net transaction value calculation) also works correctly.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: openSUSE Leap 15.2 plasma 5
(available in About System)
KDE Plasma Version: 5.18.6 
KDE Frameworks Version: 5.71.0
Qt Version: 5.12.7

ADDITIONAL INFORMATION