Thanks so much for reaching out!
I completely understand your frustration with this issue and it is something we are working on correcting.
It sounds like you have a workaround for now, however in the meantime, one thing you can do is to alter the total_sales custom field on the WooCommerce Product page that is associated with the ticket that you are trying to edit. You can change that number to reflect the actual number of attendees that you have, which will then change what you see in your Attendees tab.
You can also alter the ticket stock on the Edit Event page, where you edit your ticket.
Let me know how that goes!
Thanks,
Jaime