I made a QuickTime screen recording to check and it's recorded at 60 fps. So, I don't think that may be the issue.
I've found that some programs become quirky with MOV container, and changing it to MPEG-4 (.mp4) container often helps. Since there's no re-encoding happening, this is quite simple and fast to do.
With ffmpeg, you can use the following command to quickly change the media container of media file:
ffmpeg -i input.mov -c copy output.mp4
(Note: Works properly only if your video stream is encoded in H.264 or H.265 format. QT screen recordings are in H.264 so your use case should cause no errors).
If you aren't comfortable with the command line, AviDemux is another fantastic simple media editor and converter with a GUI that you can use. All you have to do is open Avidemux, and open the .mov video file in it. Then click the output format dropdown menu and select MP4 Muxer in it. Make sure Video Output and Audio Output is set to Copy mode and then just click the save button (or File > Save).
Once the media file container has been changed to MP4, try opening it with AE and see if the issue persists.