Continuity mistake: When the Joker gets mad at Harley, the fish she uses to defend herself changes both size and shape with each shot.
Continuity mistake: The fish that Harley uses to protect herself from the Joker changes shape and size every shot.
Plot hole: During Ryder's report, as Bruce and company watch it on TV, the camera suddenly zooms in on Joker standing on a catwalk above Ryder, and none of the crew, especially not the camera man who caught the villain, makes a comment about this. They may have thought the Joker (or rather an impersonator) was perhaps a surprise gag in the show, but since this is supposed to be a serious documentary report, it is still strange that they wouldn't point it out.
Answer: Tim Drake's origin in the DC Animated Universe differs significantly from his origin in the comics, but it also differs greatly from Jason Todd's. This version of the character is unique to this universe, similar to many of the other supporting characters with origin stories that range from being nearly identical to the comics to being entirely different from the comics.
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