SOLVED.
I had the exact same issue. Then I remembered that some of the video in my timeline had already been exported to AE with the right click ‘Replace Footage with After Effects Composition’. I forgot that once you do that, you can no long drag a sequence from PR to AE and get the dynamic link working again. Therefore, all I had to do was just delete a few of the videos in the timeline that I had already sent over and then it worked.