Use any MacBook with a touch pad. Use two fingers on the touch pad to scroll up or down. After that, hold the cmd key - text suddenly becomes unreadably small or large.

The trouble here is that after the user stopped scrolling with his finger, the view still scrolls a bit (the scrolling is decelerating). However, clicking cmd will, although the user is not scrolling any more, think that "scroll wheel zooming" is requested and will change the font size.

This is such a common task when editing - scrolling with the touch pad, then clicking CMD to invoke something -> boom, editor unreadable.

I suggest to either switch off "enable mouse wheel zooming" by default, or fix it that the "mouse wheel zooming" should only be active while the user is actively scrolling, not while the scrolling decelerates.