The Vampires of Venice - S5-E6
Audio problem: When Francesco says "Did you just say something about Mummy?", his lips hardly move because of the fang prosthetic in his mouth, revealing that the line was dubbed back in afterwards. (00:39:00)
Audio problem: After landing, the Doctor comes out and jumps in place several times. As he does, the sounds of his landings don't sync up with his motions. (00:04:55)
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.