Continuity mistake: During the flashbacks of the abusive father's childhood his own father's shirt sleeves go back and forth from rolled up to just unbuttoned.
Revealing mistake: When The Hulk tosses the abusive father across the gym his blond hair looks fluffier and darker, indicating it's a wig on a stuntman.
Chosen answer: Bruce has always been the character's middle name. In the comics he is Robert Bruce Banner, here he is David Bruce Banner. Apparently the executives behind the show preferred the name David.