Running Revaluation for a bank balance of $(482.34) at 1.4075 is giving an fx amount of $20.87. This is incorrect.
This is a very common misunderstanding about revaluation. The revaluation is actually correct. The revaluation does not revalue the balance of the account, it revalues the total of the USD (foreign currency) amount at the end of the specified period.
In this example, looking at the GL Transaction Listing of the account shows us this:
The revaluation is calculating on the Total of USD transactions of $(1,068.00). Based on the rates at the time of the transactions 1,068.00 USD is an equivalent of 1,482.34 CAD. Revaluing 1,068.00 at 1.4074 gives a CAD equivalent of 1,503.21. This difference between 1,503.21 and 1,482.34 is $20.87. Therefore, the revaluation of the account is correct.
The problem of the account is more likely related to the transactions that have been entered (in previous periods) in CAD currency, which should have been in USD and/or that the bank balance of the account is not actually in balance with the bank module. The bank module reconciles the bank in its statement (source) currency (USD), therefore, it could not have a balance of (482.34) since that is the balance of the account in CAD (functional) currency. Further accounting adjustments will need to be done in this account to bring it into correct balance in the correct currency. Once that is accomplished, it will be simpler to follow the revaluation process. See Reconciled Foreign Bank Balance does not equal GL Balance