The solution is the same. Submarine patents shouldn't exist.
When the 13th amendment was passed slave owners didn't get to "grandfather in" their existing slaves. Extreme example, but the point is sometimes old laws are so harmful to society we should not allow people to continue abusing them.
I mentioned in another comment about the Eastern District of Texas which became effectively a giant grift operation (though a recent SC case should put a damper on it). Plaintiffs sought it because they knew the jury pool would also be people who benefit from this extraordinarily corrupt, banana republic extortion racket. It was effectively like a forgettable little drive-through town that setup speed traps and decided to fund the municipality on the backs of outsiders.
There are some people who would counter this. For instance one paper notes that of jury trials, 73% of East Texas cases choose for the plaintiff, versus 68% elsewhere, "proving" that it isn't that much of a difference. The problem with this reasoning, however, is that East Texas was specifically where the cases with no merit went. It was overloaded with patent trolls and NPEs.
Actual, credible cases were seldom tried in East Texas.
Every judgment of that district should be vacated.
Pretty ridiculous how the most benign of terms all become slurs in the woke era.