Revealing mistake: When old Mary Jane Thrip kicks the bad guys' ass and runs away, her younger stunt's face is visible.
Revealing mistake: Visible ramp to allow Wonder Woman to jump over the van.
The Girl with a Gift for Disaster - S3-E19
Revealing mistake: When the gas truck crashes against the blue car, it already has a dent on the door. After the crash, the dent disappears and the door gets fixed.
The Man Who Could Not Die - S3-E22
Revealing mistake: When Bryce shows up at Dr. Akers' place and asks for the briefcase, he is replaced with an obvious stunt double, chubbier and with a funny big wig.
The Man Who Could Not Die - S3-E22
Revealing mistake: Obvious fireproof gear and a mask when Bryce escapes from the fire.
The Man Who Could Not Die - S3-E22
Revealing mistake: When Wonder Woman jumps towards the window engulfed in flames, the fire moves backwards inside the building, revealing how the jump and the scene were really shot.
Answer: Not just Grundy but everything that could link Diana and her Wonder Woman identity. A links to B, then to C.
Did Randy know that Diana was really Wonder Woman?