Attaching large files

I was wondering if anyone had a similar issue and had a solution for the following scenario.

Awesome Support File Upload Max File Size is set to 10MB

Open a new ticket and attach a file that’s under 10MB but roughly above 6MB.

It creates the ticket, uploads the attachment, saves it successfully. Everything works fine. Except instead of going back to My Tickets page like any other ticket after submitting the new ticket, it shows the Submit Ticket page / shows an empty Submit Ticket page (no values in the fields, not an empty page) as if I just clicked on Open Ticket button. If the attachment size is under 6MB, then it goes back to My Tickets page after saving the new ticket. I can view this ticket and open the attachments successfully. I just doesn’t transfer the user to My Tickets page after creating a ticket with a large attachment file.

It’s a simple WP test install with barely any plugins and theme Twenty Seventeen. I can replicate it in other installs with a lot of plugins and different themes. So this could be related to the server settings but I’m not sure how to figure that out. If anyone has any suggestion how to investigate this or what to look for, I’d appreciate it.