It seems like the opinion is focused on discussions or records of things that would incite a jury and also fall under executive privilege being used as evidence in cases related to unofficial acts. Discussions with officials and advisors about unofficial matters doesn’t seem out of bounds.
Even if some of Hicks’s testimony is technically out of bounds, if those portions aren’t especially material, serve to corroborate something else, and/or are not unfairly prejudicial, the judge could find that any error was harmless.
Also, given that it is an evidentiary issue, it might depend on whether the defense made a contemporaneous objection, which is what supposedly sank them on Daniels’s testimony.
Again, I don’t know as much as you do about the proof. I’m just giving a range of other outcomes that would still fall in line with crim law norms. The court did pretty explicitly create a two-tiered system of justice so I’m not sure “this is how it would work if it were you or me” is very helpful here.
Straight up, I’d still bet on no mistrial, but I wouldn’t bet more than like $20, and I’d see what kind of odds I could get on a mistrial.