Seems like it's not about the easement, per se, but about when suits were filed.
https://lawandcrime.com/supreme-court/in-montana-landowners-case-justices-ponder-what-happens-when-scotus-rulings-throw-a-wrench-into-statutory-interpretation/
Wilkins and Stanton said that since the sign was posted, there’s been all manner of problems on the road. They claim to “have had to deal with trespassers on their private property, theft of their personal property, people shooting at their houses, people hunting both on and off the easement, and people travelling [sic] at dangerous speeds,” — and once, the shooting of Wilkins’ cat by a passing traveler.
Frequent use of the easement has also caused land erosion, which in turn resulted in sediment build-up on neighboring properties; those properties then suffered “washout,” which is a serious concern for future use of the land. Meanwhile, the claimants contend that the Forest Service has done less and less to maintain its easement, despite their many requests for assistance.
Wilkins and Stanton eventually sued, and the dispute before the justices Wednesday relates to the timing of that lawsuit. The lower court said, and the U.S. Court of Appeals for the 9th Circuit agreed, that the plaintiffs’ lawsuit was too late as it had been filed after the 12-year statute of limitations had run.
The relevant statute is the federal Quiet Title Act, which allows litigants 12 years within which to file their claims. The legal question before the justices is whether that statute of limitations is a “jurisdictional” or a “claims-processing” rule. If the justices say that it is a jurisdictional regulation, then the rule goes to the power of the court to hear the case and the landowners will lose. If, on the other hand, the rule is simply considered a procedural claims-processing rule, Wilkins and Stanton may still have a chance to move ahead with their lawsuit, because the claimants’ lateness could be excused as an equitable remedy.
The appellants’ arguments rely in large part on a 2021 SCOTUS decision in Boechler v. Commissioner in which SCOTUS ruled against the Internal Revenue Service that a 30-day time limit in a tax case was not jurisdictional, and was therefore subject to equitable tolling. The dispute before the justices brings up an important question: should SCOTUS follow a modern trend of its own creation that require “jurisdictional” statutes to reflect their nature within their own wording, or should it stick to older precedents involving the Quiet Title Act in particular?