As rejects because the e-mail address is invalid, *but* in actuality it is really good e-mail address, but the "mailing list" e-mail is getting flagged as spam and therefore its being rejected like a regular "account not valid" response?

This is *AT SMTP* time... not Reject/Bounce After Accept.

I'm seeing more and more of this, which is against all te RFCs as far as I can see. Even if you bend the rules... its non-compliant.

I just started seeing this about two weeks ago and its spread across multiple domains... so it has to be an anti-spam tool was recently updated to have this feature. Even though we do single opt-in and some double opt-in mailing lists... we are still seeing this.

This is NOT the "user marked this as spam, even though they are opt'd in (with proof)" feedback stuff.