Are you using any plugins in your app? If not, you might want to consider using the Crosswalk Plugin (https://www.npmjs.com/package/cordova-plugin-crosswalk-webview), that way you aren't having to deal with the frustrating web view glitches that occur on various Android versions.
Also, when this issue occurs, can you see anything on your device's console (adb logcat)?
Thanks, I've not heard of Crosswalk before and looks to be a good idea! It seems to be available via PhoneGap Build so I've added it (v1.3.0). I've still got a bit of playing around to do - it doesn't seem to like having CSS styling applied, or work at all with remote videos - but I've got it working for my current main use case.
Seems a bit bloaty unfortunately, my tiny test app went from 3MB to 60MB, just by adding Crosswalk! But if it works then I can deal with that. :-)