1. Open Settings application
2. Under System settings, go to Accessibility menu. (On some devices you may change tab, or you may find it under Personal settings)
3. Tap Magnification Gestures.
4. Make sure to turn it off, otherwise you can Pan or Adjust zoom level by tapping the screen, as described in the menu
I'm using elipsis 7 and literally just figured it out. I type so fast that it thinks I triple tap sometimes.
Settings--systems-tap on accessibility--system-tap on magnification gestures. Turn it off.
Thank you so much Trenzalore, for getting what the problem was (typing so fast that it seems like a double/triple tap) and for providing a solution. It was SO annoying and I couldn't find a solution in keyboard settings or Language and input.
On my Samsung Tab 10 in, it is:
Settings » Device » Accessibility » Vision » Magnification Gestures -- tap or slide slider until On changes to Off (Mine was stubborn, so I had to try quite a few times)