Answer:
If a transaction is being reported as part of a CTR (because more that $10,000 in cash-in or cash-out transactions were conducted by, or on behalf of, a person), the reporting bank must identify all known conductors of the transactions and all known persons on whose behalf the transactions were completed.
The checks that were cashed were payable jointly, and, because the wife also completed a cash withdrawal of $10,000, you have $12,500 in "cash out" transaction to report. The $2,500 in checks was jointly payable to the husband and wife, so cashing them was done on behalf of each of them. They both get listed on the CTR.