@komatthew The likeliest explanation is that you were not accounting for the CD interest in such a way that the CD balance was increasing by the interest income each period.
To give a proper answer, you'll need to explain how you were recognizing the CD interest income in your books.
A standard way of doing this is by way of the Deposit function to the CD account using Interest Income as the source account; this recognizes your interest income at the same time as it increases the CD balance.
