My guess is that the righthand doesn't know what the lefthand is doing. Check with your attorney. If you do not have one, contact the Chester County Court Administrator's Office at the Court House. Given them your name and court docket number, and I'm sure they will be able to explain the relationship between the notices you have received.
As the other attorneys have suggested, it's probably just an oversight by the common. It wouldn't be the first time, and won't be the last. Good luck.
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