The second time David becomes the Hulk, he is wearing light tan (almost white) pants, but when he Hulks out, he is wearing rust color pants.
When David Banner & Renee Dubois open their office to find a crowd gawking at the Voodoo artifacts left hanging on their doorway, the same frame showing the extras is reversed to make it appear that the crowd is larger than it actually is, showing the same extras first at right and then at left. This is repeated at least three times back and forth easily revealing this production money-saving goof.