Opacity masking cuts off part of video

[ThatOneDuck]

I am trying to add an opacity mask to one of my layers, but when I do it cuts off a little bit of the left side of the video the moment I add the mask. I tried rendering the video to see if it was just a visual bug in Premiere Pro, but it renders with the cut off side. What causes this?
First image is before the mask is added, second image is after the mask is added.
(These are 2 layers on top of each other, the top layer is the one that matters in this situation.)

 

 

[Ann Bens]

Make sure windows OS scaling is set to 100%

[ThatOneDuck]

This is already the case.