The FD product's exception mapper fell back to a bare "Unknown data integrity issue with savings product." for any DB error it didn't recognize, with no detail -- unlike its sibling class for regular Savings products, which at least appends the underlying error. Added a specific, actionable message for the numeric-overflow case (an amount field entered too large for its column), and made the generic fallback include the real detail too. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>