Yeah, SES puts those soft bounces on suppression list too after a number of failed attempts. That is actually an issue we've struggled with. A large number of users using a mail service with just 10MB of storage. Those mailboxes were always full and we got soft bounced over and over until SES put them on suppression list. User contacted support and got told to clean out the inbox to make room but emails could still not be delivered until we had manually remove the address from the suppression list.