Good afternoon Cath and welcome back!
Thank you for reaching out to us.
I would love to help you with this topic.
When a ticket is purchased it gets stuck at order ‘processing’ and has to be manually completed. Since the inventory doesn’t update until an order is complete it makes the plugin pretty unusable unless tickets come off the inventory when a payment is made.
You are correct. By default, a ticket order is set to processing.
However, this behaviour can typically be changed with a snippet or a third-party plugin.
The most efficient one being https://docs.woocommerce.com/document/automatically-complete-orders/
If, for some reason, that does not work for you, there is a chance that something is blocking the status change. Most of the time that would be another plugin or a snippet.
As a first troubleshooting step, could you please provide us with your complete system information in a private reply using the instructions found in the following link?
https://theeventscalendar.com/knowledgebase/sharing-sys-info/
Have a good weekend,
Geoff B.