The Christmas Invasion - S2-E2
Audio problem: When the Doctor is proving his identity to Harriet Jones by telling her about when they were trapped together at Downing Street, his words don't match the movements of his jaw when we see him from behind - the timing's all off. (00:40:55)
Audio problem: When the Doctor confronts Mr. Finch/Brother Lassar in the school pool, there is a wide shot of the Doctor from across the pool as he asks Finch, "Who are you?" His mouth isn't moving. (00:23:10)
Audio problem: Mickey asks Rose why the Daleks are keeping them alive. When she responds, "They might need me," her mouth movements are not in sync with the words. (00:09:25)
Chosen answer: 1) When Stephen Moffat took over he ignored a lot of what had been developed before (there is not in-universe answer). 2) It would have killed Rose, so the Doctor absorbed the energy. His body regenerated before the energy could do a significant amount of damage that would prevent regeneration.