Peace broke out last week between gene sequencing rivals Illumina Inc. and Qiagen N.V. But before lawyers could pack up their files, a new patent war was taking shape.

On Friday, Illumina, Columbia University and its licensee Qiagen settled their 5-year-old patent litigation. Qiagen agreed to stop using with its GeneReader machine a method for labeling nucleic acid molecules that was patented by Illumina.

Judge William Alsup, who’d enjoined Qiagen from selling the machine in the United States last fall, approved the parties’ consent judgment. Qiagen in turn dismissed a lawsuit it had filed in Delaware and its Federal Circuit appeal. Financial terms of the settlement were not disclosed.

But three days earlier, on July 18, Columbia obtained a patent on a different gene-sequencing chemistry. The very same day that patent was issued, Columbia and Qiagen went back to Delaware to sue Illumina again for patent infringement.

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The lawsuit shouldn’t have come as a surprise to Illumina, the plaintiffs note in their complaint.

“Illumina is a large and sophisticated company that has had patent litigation in Delaware with Columbia and Qiagen, and thus, on information and belief, Illumina monitors patent applications involving DNA sequencing technology and was aware of the content of claim 1 of the ’358 Patent on or after it was published on March 30, 2017,” states their complaint, which is signed by Jack Blumenfeld of Morris, Nichols, Arsht & Tunnell.

Fitzpatrick, Cella, Harper & Scinto and Ballard Spahr also represent the university and Qiagen.

Illumina, which is represented by Weil, Gotshal & Manges along with Ashby & Geddes and others, is in a race to move next-generation gene sequencing technology beyond big research laboratories and into everyday clinical settings. San Diego-based Illumina is the biggest player in the industry, but has been focused primarily on large research institutions. As the cost of the technology dropped, Qiagen began marketing its less expensive machines to hospitals and clinical labs for use in personalized medicine.

Alsup enjoined Qiagen from selling its machines in the United States last September, saying the company had “pirated” Illumina’s technology. The judge called it “a rare and powerful case for the unusual remedy of a preliminary injunction.”

The U.S. Court of Appeals for the Federal Circuit sounded similarly hostile during oral arguments in January. Ballard Spahr partner Robert Baron had urged the court to let Qiagen try its case before enjoining it, but also alluded to Qiagen’s efforts to design around Illumina’s technology.