Kitchen Display ticket reappears after a while

I’m using kitchen display ticket system using task printer. (Link at bottom)

As title says, I have sneaky tickets that reappear after a while, after they were set as complete. They tend to reappear a few times after setting as complete every time. This isn’t every ticket, just a few here or there, also can be from waiters that are not on duty the day and can be from any time in the day. It is generally just from todays work period.

Does anyone have a suggestion where I can go look?