Streamlined Moderation Approvals, Now in All Outlook Clients

Is there a way to opt out of this?  When we try the approval cards we get the error:  Failed to validate the signature of the actionable message card.  None of our troubleshooting has worked, and we rely heavily on moderation for a specific type of bad email trapping in our environment.  (in the hundreds per day range)  Our moderation mailbox is a mailbox that multiple people use, but even if we open it in Outlook Webmail, using our normal username, and select to open the shared mailbox, we get this failure.  The volume of email is too high to send moderation emails directly to named people.  The mailbox is setup as a user mailbox with delegated access.  We have not tried a shared mailbox, but documentation on Action Cards seems to imply Shared Mailbox is even harder to implement than straight user accounts.  If we cannot opt out, do we use standard support to try to resolve this, or do we need to refer to a specific support team when opening a support ticket?