Reconciling a foreign payment on a Bank Statment

We are currently experiencing having a problem reconciling foreign payments for one day only.    The process has worked normally for all other days.

When reconciling a foreign payment line users enter the original amount (base amount) and the system then calculates the user rate based on the GBP value line and the original amount.    The statement line is then matched to the payment and normally the difference would be applied to the gains and losses account, leaving no balance in the amount remaining box. 

However for one day the system is showing an a value in the amount remaining box meaning we are unable to reconcile this line.    This issue has affected multiple currencies.