> particularly in cases like this where the acts in question weren't necessarily a single event but progressive activity is the kind of question which is the bread and butter of an appeals court.

No, findings of disputed fact - like when Musk had reason to know of his injury, are determined by a jury (or a bench judge). Appeals courts examine whether the law was applied correctly, not what the jury's fact finding was. There may be an avenue of appeal that the jury was improperly instructed, but determining questions of fact are exactly -not- the bread and butter of an appeals court.