pixel dropping

Hi there, Ive recently uploaded a new video and i get pixel dropping around where i have time lapses with in the video, which are not in the original out of premiere: 01:32 02:05 03:42 03:56 05:29 06:15 06:48 10:19 Definitely most noticeable at: 01:32-01:42 My question is why may this be...