Text size jumping

Windows 10, most recent build, Scrivener 3,

I’ve noticed sometimes especially when I scroll down to the bottom of a document in either the main editor or with the ‘notes’ section for that document open, the text in whichever window the mouse is active in suddenly resizes without any other intervention. I can’t quite replicate the exact movement that is triggering this, but I’m using an Apple 2012 trackpad (replaceable batteries) run through Windows adaptive software (Magic Trackpad).