I noticed that recently I can't zoom properly in Quick Look when I preview image files. When I press the space bar, I can zoom normally. After that, I can pan the picture in the Quick Look window. However, after panning the picture, I can't zoom anymore.
I tried this on another MacBook Pro running macOS Sierra just like mine, but it seems like it works normally (i.e. in a Quick Look window you can zoom, pan, and then zoom again). This suggests that my problem arises from something that I installed on my machine.
How would I go about troubleshooting this issue and trying to find out what's preventing me from zooming after panning when previewing pictures with Quick Look?