The Emails marked preferred on RE are also marked as preferred on AB.
When the same email is marked as primary or non-primary, the system does not pull both emails, cannot determine which is preferred, and randomly marks any email as primary.
To ensure the preferred email is maintained as such on Almabase too, ensure
There are no duplicate emails on a record with one marked preferred.
OR
Please don't pull the email type with the duplicate email into Almabase. You can set this up when configuring the database pull setting.