Internal Testing: Email List and Notification Issues on Google Play

A developer is building a private app intended for perpetual internal testing. They have added a private Google account to their tester email list via the Play Console. Despite uploading an initial version, they are not receiving any notifications or emails on the private account's device. The developer is seeking clarification on whether manual triggering is required or if sending an invitation link is the correct approach, given the existence of an email list.