You need to modify the localconfig variables that rewrite that data, using zmlocalconfig. For example:
[zimbra@freelancer ~]$ zmlocalconfig | grep smtpd_data_restrictions
postfix_smtpd_data_restrictions = reject_unauth_pipelining
The last one you'll likely have to modify via postconf.
zmlocalconfig | grep client_restrictions
postfix_smtpd_client_restrictions = reject_unauth_pipelining
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