Duplicate WBS Phase Job

So, we use Project Entry pretty extensively for our design and CAD folks. Each WBS Phase represents a different step needed in the process.
They’ll click the button to create a WBS phase job and that’s what they log their time against.
Every so often, we see two WBS phase jobs under a single phase and the duplicate one is usually a shell of a job, missing dates, etc. The change log shows the project manager who created the proper job also created this job, but none of them have any clue on how the second job appeared. The only way I can think of to add that second job is to do it through Job Entry and link the project to it, but the project managers claim they’ve never seen Job Entry before, let alone know how to use it. Plus, it’s engineered with no required by date, so I’m inclined to believe it. Any idea how that second job may come to be?
(None of the customizations/BPMs we have involve creation of a job)