Bug in email forwarding via pipe to program

I have v2.0, build 3 on CentOS 7 and have been testing it for a few days. All works well in general with no issues. I am now testing email forwarding and piping it to another service. All also works well and the forwarding works, BUT only if the incoming email comes from outside of CyberPanel. If instead I use webmail (rain loop) on the same CB server to send the email, it goes into the inbox and is not forwarded. But not if I send the email from my local mail client outside of the CB mail server.

Is this a bug or a “feature”? I would think no matter where the email is coming from, the email should be forwarded properly.

Thanks for any info.