Why speaker diarization DER on Ego4D dataset is so bad?

According to: pyannote/speaker-diarization · Hugging Face,

the performacne of PyAnnote speaker diarization on Ego4D dataset is very bad (very high DER rate):
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  • Is there a reason for this bad results ?
  • What is the different between Ego4D dataset and the other datasets that the performance is inferior ?