I edit the video version of a podcast and so the videos I export are around an hour to 2 hours long with 3 camera angles so I use the Multicam feature and layer many different photos on top of the footage every time I make a video. Only sometimes will the video glitch and then when I cut smaller clips from the show using auto reframe sequence 9 times out of 10 it will severely glitch. I have tried exporting with H.264 and high bitrate, medium bitrate.... all the options under H.264, even maximum render quality. Nothing seems to help. and before you ask, yes I render between each step of editing.
Could you share a screenshot of the video properties for the source video? Which version of Premiere are you currently using? Also, please let us know your system specifications (OS, GPU, RAM, CPU).
Under your export window please go to Video> Encoding Settings > Performance and use the drop-down box to select Software encoding if not already selected and render again to see if the problem is still persistent.