developments show it was anything but normal. Seems like Mueller promised Flynn Sr. that he wouldn't prosecute Flynn Jr. if Senior pleaded guilty and agreed to testify against a number of defendants, and that he concocted this agreement on the side to avoid his Giglio obligations to turn over all agreements with Flynn Sr. to the other defendants, thereby depriving them of the right to fully cross examine Senior on his motivations to testify.
Not normal.
Of course we now know that Mueller is a doddering old fool who didn't even know what was in his own report and should be at the Del Boca Vista early bird special.
Link: https://thefederalist.com/2020/04/27/robert-muellers-case-against-michael-flynn-is-about-to-implode/