SharePoint copying files back to originating folder in off hours

Hi all,

I work in IT, and we have employees using SharePoint to collaborate on work orders. Their work flow is to create the work order in a folder for new jobs, and after edits are made, they're moved out of the new jobs folder into the parent folder. Our employees are noticing that the edits that are made to the work order sync just fine across employees, but sometimes the file will copy and place itself back into the new jobs folder even after it was moved. Usually this happens in off hours around 10pm-2am and we're struggling to figure out why. My assumption is that someone has it open on their computer originating from the new jobs folder and it syncs during off hours, putting itself back in the new jobs folder thinking it belongs there. I'm not exactly sure how SharePoint works, though, so I figured I'd ask the question here to get a more educated answer. Would that be the cause, or could it be a general issue in how the folders are being updated? Why would it sync just fine for everyone, and then suddenly copy itself back to where it was first created?