[2.1.6] Exchange rate of transactions is not reset correctly when account currency is changed

If you create an account in the default currency (e.g. EUR) and create a transaction there (e.g. 50€) and then change the currency of the account to e.g. “USD” then the transactions are converted correctly (in this case e.g. 52$).

However, if you now change the currency of the account back to the default currency EUR, the transactions are converted incorrectly and displayed as 52€).