I've tried to replicate the same thing twice and its slightly different yet doesn't work at all

I want a line to follow this motion path. On the picture where the keyframes are little dots, it works how I want. On the picture where the keyframes are squares, it doesn't do anything at all. My process was as follows:

Motion track a video

Copy that motion onto a null object

Create a shape layer

Use the pen tool to make a single dot

Add a path

Apply the position data from the null object to the path

--At this point on the first try, it made a shape exactly in the shape of the path (what I wanted)--

Apply "Trim Paths" and then add the appropriate keystrokes so the path is drawn over time

Because I didn't like the smoothness of the initial motion tracking, I went and adjusted a keyframe to make it smoother, and then ran through the steps again. Except this time it didn't work, as shown in the photos.

Can anyone help me figure out this minor problem that causes the whole thing to not work? Thank you.

Works how I want, but the motion path is not preferredMotion path is smoothed, but it doesn't form a shape