Well, the size of the text increase could be due to Zoom in/out. I have code which is mostly never conflict with Two finger scroll if we do the scroll just like it should be done. The zoom in/out will get trigger only if the fingers gets spread instead of staying close to each other. So, explain how you do scroll and when exactly happens this text increase with an example so i can try that and see if its there.
And what is your problem with keyboard layout? What kind of keyboard layout you have?