Hey,
Thanks for reporting!
To clarify, we have the database ticket id and also the ticket number. The number is what you're able to adjust on Admin Settings > Ticket.
I can replicate this only on /client/ticket_view_all.php: we seem to display the database number instead of the client-facing ticket number. That has probably been this way since I initially wrote it over a year ago! Fixed in develop: itflow-org/itflowc273cab
Are you seeing this anywhere else? Feel free to test on develop.dev.itflow.org (it gets wiped with each dev commit though!).