Turn off text size changer with volume rocker on S6

[AC Question]

I dislike the setting when I am using text or multimedia messaging that if I bump my volume keys the font is either huge or tiny!
Is there any way to disable this function on the Samsung Galaxy S6? I've tried the settings pages and read the forums for older devices and the option is missing to deselect it.
Can anyone help me out? This function is more than frustrating!