PDudeP Ah, ok -- the description for HELO seems a bit misleading. It explicitly states to use the mail servers. I don't have an rDNS setup on my App/DB server. Let me do that and switch the HELO name away from the mail servers rDNS hostname.
I can see that some of my forwarded messages are dropping for spam aswell now... Appears to be picking up a bulk of the spam score from tests like:
"From and Auth And Replyto Do Not Match"
"From Neq Envfrom"
"MB Base Diff Rpto"
"Neural Spam"
"New User"
Not sure how some of these can even be addressed since that's the nature of the forwarding...
As for the contact submissions -- it looks like it's racking up spam score related to subject lines, and content. (common subject names for spam, and being flagged as suspicious content) I'm going to re-work the subject line created by the contact form submission to see if that improves anything.
Have a ticket in with MailBaby/InterServ as-well.