The exact same thing is happening to me; it just gets stuck in an endless loop. I’ve noticed it happens after I take the glasses off for a while or put them back in the charging case.
The only workaround I've found is manually turning them off using the switch on the left temple, but I'm worried about wear and tear and eventually breaking it. When it’s stuck in that loop with the startup sound and the green LED, it becomes completely unresponsive. Even my WhatsApp voice notes end up with several seconds of silence while the glasses are looping.