We ran into issues with CDC when tables had a lot of TOAST columns. The WAL records don't include the full values unless you set REPLICA IDENTITY FULL. Does Streambed handle that, or do you need the extra config?
Currently, Strembed expects REPLICA IDENTITY FULL for getting the before and after value of TOAST column. Since we have the data in object storage, we could populate it without the need for REPLICA IDENTITY FULL. Created an issue https://github.com/viggy28/streambed/issues/25 to track this feature.