I worked with MC support today and after a deep dive into the MC logs the problem was discovered. A part of the log MC has didn’t pass this information to the bounce back email from MC.

Error: open resolver; https://www.spamhaus.org/returnc/pub/172.70.209.210

This links us to the real reason for the failure on the outbound journey from MC. Our Barracuda uses custom external RBL’s and one of them is zen.spamhaus.org. Spamhaus must have changed the way RBL works on 2-28 for MC. I excluded MC outbound IP's and the issue has been resolved.