This is so if another editor needs to make changes to the sequences and re-export the metadata is intact regardless of whomever opens and uses the team project. So far, we have not see the metadata sync like everything else does.
Metadata for media-based clips is shareable in a Team Project, but I'm seeing the same issue you are for metadata attached to a sequence via the Metadata panel. The metadata is visible to the user who creates it, but is not shared. I will file a high-priority bug to make sure we track this down. I'm very sorry for the inconvenience.