Mouse position not being saved every frame?

OS: Win10
PsychoPy version: v2020.2.5
Standard Standalone?: yes

What are you trying to achieve?:
I coded a visuomotor rotation experiment in which participants have to make reaching movements from the center of the screen to one of two possible targets (both in the upper right quadrant). I need the entire trajectory of the movement so I’m saving the mouse position on every frame. But when I look at the data output (see figure), I only see the starting trajectory and then a few datapoints at the end of the trajectory.

What did you try to make it work?:
I checked my code and went back to the raw data from the csv. file and this is all the data I have. I thought that the problem might arise because I only present endpoint feedback (so the cursor is only visible at the end of the trajectory) but I am saving the mouse position the entire time so I should have the data…

What specifically went wrong when you tried that?:
I don’t see the entire trajectory and I don’t understand why. The movement duration is between 400 and 800ms and my frame rate is 60Hz so I should be getting way more data points. Does anyone have an idea what’s happening here?

Figure explanation: the two blue circles are the targets, the red stars show the endpoint of each movement that is starting at the bottom of the screen on the left. There we also see the start trajectory of the movement. There are also a few random data points between start trajectory and endpoint.