If the judge acted on the case he must have known about it. If he knew about it it was before him. If it was before him he had jurisdiction.
A court case need not be filed for a judge to act. Often a judge will determine if a case may be presented. Judges may become involved before a prosecutor or other agent of the court files an action. Granting a warrant is a case in point.
I did some further digging. The judge acted on an expungement motion from one of the Duggar sisters. That's where the judge got jurisdiction.
Although the expungement is pretty much moot at this point. The reports are already out in the public. This just prevents further release.