(a) If the original check is received or recovered by the claimant after he has requested the agency to issue a replacement check, but before a replacement check has been received, he should immediately advise the agency and hold such check until receipt of instructions with respect to the negotiability of such check.

(b) If the original check is received or recovered by the claimant after a replacement check has been received by him, the original shall not be cashed, but shall be forwarded immediately to the agency that authorized the issuance of such check. Under no circumstances should both the original and replacement checks be cashed.