"Command rejected" on some redirected mail

Where have two mail servers 

• companyA.com (Office365, not routed through Sophos Cloud)
• companyB.com (Exchange 2016 On-premise, routed through Sophos Cloud)

Some CompanyA.com emails are redirected to companyb.com. For example, user1@companya.com will redirect to user2@companyb.com. Normal mail works fine this way, but Microsoft Teams notifications seem to fail with the following example error

mx-01-us-east-2.prod.hydra.sophos.com

Remote Server returned '554 5.7.1 <mx-01-us-east-2.prod.hydra.sophos.com #5.7.1 smtp;550 5.7.1 XGEMAIL_0003 Command rejected>'

The support engineers found that sophos cloud wasn't properly evaluating the to address as it was still thinking it was going to user1@companyA.com instead of user1@companyB.com. This worked on our SG210 just fine previously and only became an issue since moving to the cloud gateway.

The engineered said the best place to post this for product improvement is on the community so here I am posting it here. For technical references, Sophos employees can see ticket 9893739

I believe this is very much similar to this issue that was previously resolved.
https://community.sophos.com/products/sophos-email/f/general/112954/g-suite---group-mail-forwarding-rejected-by-sophos-central