The Sandbagging Trap: Why Post-Decision Inventorship Fixes Cannot Save Your Patent Claims
In Implicit, LLC v. Sonos, Inc. (2026), the Federal Circuit ruled that obtaining post-decision certificates of correction to alter inventorship cannot retroactively rescue patent claims previously invalidated during an Inter Partes Review (IPR). The court determined that using 35 U.S.C. § 256 to add an omitted inventor after losing on the merits constitutes improper "sandbagging," affirming that such corrections cannot be used to introduce new priority theories after a final written decision.
The ruling highlights that while Section 256 does not impose a strict statutory deadline for administrative inventorship corrections, a party's right to use those corrections to gain a tactical advantage is constrained by standard litigation rules. Because the patent owner had all relevant inventorship evidence from the beginning but waited to correct the record, the court held that the new antedating argument was forfeited.
This decision underscores the strategic imperative of thorough, upfront inventorship analysis and timely corrections. Proactive documentation of all contributors, early evaluation of potential antedating evidence, and swift § 256 actions during challenges can help protect hard-earned IP assets from being invalidated by correctable issues.