Combinig sampleImage and valueAtTime

Hi

I have a layer which scale is using sampleImage to set it's value. So it samples the color from a different layer and sets it's scale values accordantly.

I then have a script which loops through every frame, gets the value using valueAtTime and sets it as a keyframe. Essentially baking the transformation to keyframes.

This doesn't work. If I have any other expressions it works. So it seems it is a problem with the sampleImage. It's like it doesn't have time to sample the image before it runs valueAtTime.

I tried moving the playhead to the given time before calling valueAtTime. This works a little better. But still only about half of the frames will sample the right value.

Last I tried caching all frames first. Still, no luck.

Any ideas how to solve this?

Thanks,

Jakob