Growing up, my grandparents lived on a lake in far northern Minnesota. Naturally, one of my favorite pastimes (during the 6 hours a year when the lack was not frozen) was throwing objects into the lake to see the splash. Stones, screws, turtles, siblings, turtles and siblings together in a move I called turtle-terror-soup, all were grist for the splash mill.
Famously, once the splash settles and the turtles have returned to doing whatever they do, the waters turned calm once again. A passerby moments later would have no knowledge of the true chaos that had just passed. This is the way of true ripples.
Metaphorical ripples, however, are a bit trickier, as evidenced in last weeks ruling in Agilent Technologies, Inc. v. Axion BioSystems, Inc., C.A. No. 23-198-CJB, D.I. 486 (D. Del. Jan. 22, 2026). The defendant, Axion, had succesfully moved to strike portions of Agilent's rebuttal report on invalidity under Pennypack.
shortly after that ruling, but months after the service of all the relevant reports, Agilent moved to strike all of the portions of Axion's reply that were responsive to the stricken rebuttal report. Agilent also cited to Pennypack, and generally noted that such a holding was a necessary "ripple effect" of precluding the rebuttal opinions.
Judge Burke denied the motion, finding Pennypack inapplicable:
The problem with Agilent’s position is that it is entirely too late to argue that the opinions at issue are untimely or an improper disclosure pursuant to Federal Rule of Civil Procedure 37. As Axion asserts, “[i]f portions of Dr. Fair’s reply report had really been untimely or of an improper scope, Agilent’s motion to strike should have been filed six months ago, shortly after the May 21 reply report and Dr. Fair’s May 28-29 deposition. But Agilent said nothing, and even relied on some of this evidence to support its own summary judgment motions[.]” That’s because in truth, Dr. Fair’s reply report was filed on the appropriate date, and it responded to portions of Dr. Frazier’s rebuttal report. And so, the Court cannot find that the opinions at issue violate Rule 37. And in the absence of an untimely or improper disclosure under Rule 37, the Pennypack factors simply do not apply here.
Id. (internal citations omitted)
The Court also found that, because the opinions at issue did not relate "solely" to the stricken rebuttal opinions, they were not necessarily moot and thus need not be stricken on that ground:
Dr. Fair’s opinions at issue “relate to opinions in his [own] opening report” about subject matter (i.e., Axion’s invalidity case regarding certain prior art references) on which Axion bears the burden of proof at trial. . . . And Agilent apparently intends to challenge Dr. Fair’s opinions regarding the subject claim limitations and prior art on cross-examination at trial. Therefore, the opinions at issue do not seem to be “moot” or “irrelevant”—they seem to be very much bound up in live disputes that will be assessed at summary judgment and/or at trial.
Id.
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