Momentary zoom in when scrolling with mouse wheel - Windows 10 and IE

My Google-fu is failing me on this. I just got a shiny new PC with Windows 10 for work, and more often than not, when scrolling through a website with the mouse wheel, the page briefly gets larger, returns to normal size, and scrolling resumes. Most of our internal sites do not work with Edge, so I normally only use IE.

What the heck is going on and how do I stop it?