Pasting not working, I can't find a solution

So I realize this has been asked many, many times. However I have been unable to find a solution insofar. I have tracked a screen in Mocha with the intent of replacing it. The track works perfectly and adding the clip intended to replace the screen while in mocha works perfectly. However, in AE the track drifts off and does not stay on the scree. Here’s my process

Create an X-Spline layer around the screen
Track said layer
Click “export tracking data”
Select "After effects corner pin [supports motion blur]
Click copy to clipboard
Select the desired insert
Move playhead to 0
Press Ctrl-V

The track is off, and not by a certain predictable amount. It moves around seemingly randomly.
I have tested this with a solid with the exact settings as the comp, and the issue persists, so it’s most likely not and issue to do with size or resolution (both my files are 1080p in any case)

I appreciate any possible help.
Edit: they are also the same framerate, 29.97 fps

Is the insert a different size as your comp? Please try to precomp your paint in a comp the size of your original comp, fit the insert to the comp, and apply corner pin as normal. Alternately use align surface and precomp your paint in a comp the size of your original comp and apply an aligned surface corner pin as normal.

Try that and let me know?

Cheers,
Mary

So I think I have a sort-of idea of what the problem is. In AE (and Premiere and Quicktime) the clip I’m using has 198 frames. Importing into Mocha (with the same path), Mocha thinks the video has 245 frames. They are at the same framerate. I have tried importing only the first 198 frames to Mocha but that does not help. Looking at the video in each application shows that Mocha and AE have different ideas about which frame is which. They are using the same file. Can you suggest something?

On your reply about comp sizes, I have tried using a solid the same size as the comp and there is no improvement.

In AE, have you checked both the clip frame rate AND the comp frame rate? That’s usually the culprit, AE will interpret the footage differently sometimes.

Both the comp and the clip are 29.97 fps in AE and Mocha.

You might have to email me the shot and the file and I will look at it on Monday, I will see if I can see what’s wrong with it.

Okay, thanks so much.

Did you figure this out or do you need to email me the shot? Email me at maryp at boris fx dot com.

Hi sorry,
I don’t have access to my main computer with the AE files on it currently. Thank you so much for your help and willingness to remind me. I’ll get the files to you as soon as I can. Sorry about that.