Google Workspace accounts may be configured to require a re-authorization for connected apps after a set length of time which can be a reason for Pipeline to request re-authorization of your email sync when that time has expired. We do not have visibility or access to your Google Workspace Account Settings but have put together a list of resources to help your Google Workspace account admin make the needed updates to resolve this.

Google Workspace Update Article on Introduction of Option to "Exempt" Apps from Session Length Settings
Google Workspace article "Control which third-party & internal apps access Google Workspace data"
Google Workspace article "Set session length for Google Cloud services"