Why does the video in After Effects lag?

Question

Video

I throw the pre-filmed material (4K 30 fps video from an iPhone) into After, after which I create a new composition from it
. And such an added video lags (that is, part of the video can be displayed slowly, part just jumps from frame to frame, slows down, as it were). Although the files are normal, they are displayed normally in any other program.
I met this before, when files with different fps were added to one project, but here I added only 1 video and created the composition by dragging this video to Create new comp
. What could be the problem? Because when converting a file to mp4 on different sites, the problem disappears, but the quality is lost, as well as colors
These are ordinary videos in which you just need to cut the sound and cut it minimally, so I would like to find a quick solution to this problem.