On 6/18/22 19:47, Markus Winkler wrote:

selectively turn off automatic BCC recipients

Or you could just as well set
-o sender_bcc_maps=hash:/etc/postfix/back-to-sent-folder
selectively for the submission port, or for port 10026. If this setting is potentially troublesome it might be more future-proof to apply it selectively, rather than selectively override it.