Second window won't stay zoomed out

I'm using a drawing tablet with a screen to edit photos, I keep one window open on a monitor above it to see an overview of the image I'm working on while I'm zoomed in and painting on the drawing tablet. Yesterday this functionality stopped working, now when I zoom in or move around on the drawing tablet, the second window of the same document on the monitor above zooms in and moves around with it, which entirely defeats the purpose. I did not change any settings. I would really like this to work as intended, if anyone has an idea of why this randomly started happening it would be much appreciated!