Some of the evidence used at trial came from his time in office. That's inadmissible, now. "Official acts" is pretty vague.
We'll see what the judge says.
It may be inadmissible NOW, but it was admissible THEN. Ex post facto goes both ways, which is why governors are pardoning marijuana convictions now that it's legal; making it legal doesn't erase previous convictions ex post facto. Making official acts protected doesn't erase previous convictions.