Secret Wars, Chapter 3: Doom - S5-E11
Continuity mistake: After the Beyonder ends the war, he teleports everyone to a floating chess board in space, with Dr. Doom lying near the edge. When the shot changes, Doom has moved closer to the middle of the board. He is unconscious so he couldn't have moved.
Secret Wars, Chapter 3: Doom - S5-E11
Audio problem: When the Lizard says "Yes, Spider-Man," his mouth is wide open and motionless.
Secret Wars, Chapter 3: Doom - S5-E11
Revealing mistake: After Dr. Doom has stolen the Beyonder's powers, he demonstrates the powers to Ben Grimm in his throne room by teleporting Red Skull, Dr. Octopus and Smythe off the planet. Next he teleports all the heroes to his throne room, and the shot of all the heroes is from two episodes prior when all the heroes were battling the Lizard. This shot of the heroes also includes Ben Grimm in form as the Thing, meaning Ben Grimm was in two places at once. Spider-Man, the Lizard and the rest of the Fantastic 4 were also already prisoners in Doom's castle, which means they were all in two places at once as well.
Secret Wars, Chapter 3: Doom - S5-E11
Other mistake: This series is in the same continuity as the other Marvel animated series from around the same time - X-Men, The Incredible Hulk, Iron Man, and Fantastic Four - by virtue of each aforementioned show crossing over with at least one of the others. However, in Fantastic Four, Dr. Doom had a German accent, and in this episode he has a Russian accent.
Suggested correction: It was a part of the character's redesign. The writer of Spider-Man, John Semper Jr, disliked the Fantastic Four cartoon to the point that he not only changed characters' designs but their voice actors as well.
Redesigning the character is not a valid correction, because it still creates a contradiction within the shared universe. Even under the pretense of redesigning the character due to not liking the previously established version, it would still be a deliberate mistake.
Phaneron ★