Just play a bit with this on a Nexus 5 and a Galaxy S4, both with 4.4.2 (don't have any LG G2's around).
If I open a wide HTML message, and double tap once, it zooms out to fit the screen. However, if landscape more (but not in portrait), if I double tap again, the message zooms out even more, adding white margins on the sides.
So there definitely is a difference, but it's not my app doing it. The zooming (and how it's wired to double tapping) is handled by system code, WebView, which is all new in 4.4.