The problem may be because of revised TDS returns being filed by the bank after issuing you the Form 16A. Or if the additional entries appearing in Form 26AS is significant and appearing to be not relating to yours, it may be because the bank erroneously updated your PAN to transactions relating to some other customer.
These differences are all because the TDS returns can be revised any no of times even after the issue of Form 16A. Hence, always check whether the transactions in Form 26AS is final and relating to yours. If so, don't bother about the Forms 16A issued.