This only started occurring after updating to 1.17.2 (from 1.17) and applying the draft save error fix (https://github.com/osTicket/osTicket/pull/6379).
When submitting a ticket, instead of loading the ticket details page for the newly created ticket, the client login screen is displayed instead.

The URL, and even the page source, correctly show and reference the tickets.php page for ticket details. Hitting refresh/F5 will load the correct page. Tested in Chrome, Edge, Opera and Firefox. Haven't been able to replicate it within the same login session, and seems to only occur for the first ticket submission in a fresh session.
Looking at web server logs, the closest thing I can find to a possible error code/message is:
