I am facing the exact same issue on my iPad as well. I can hear the audio playing in background even though I closed the browser.
I tried it with this demo link http://fregante.github.io/iphone-inline-video/demo/
Once we start the video and can hear the audio, even after closing the browser, the audio continues.
Thanks for addressing this! Came here because of this exact issue – people reported if they play videos from a Twitter feed the audio takes over and they have to close the game/repoen to get it back. I just downloaded the 2.0.3 update and hopefully that will fix it. Thanks!