Another correction, Lindsey Halligan wasn't a judge, she was appointed as a temp DA.
Per CNN Live: It is that Halligan 'unlawfully appointed'. Judge has ruled that the indictments can be refiled by a different prosecutor.
Halligan was appointed as a temp prosecutor. Temp appointments only last 120 days, but she was allowed to remain in the position unlawfully.
I had a temp federal appointment as part of my career, although it was a 3 year appointment. It had to be and was renewed every three years.