Ion-nav-back-button has wrong icon (beta.14 nightly)

I am seeing that when running on an android that my nav bar back button is not showing.

This shows fine when running in the browser (and with device emulation on), but running on the Android emulator and actual devices it seems that the icon is being set to ion-ios7-arrow-back. If I change this manually using the dev tools to the ion-android-arrow-back then it shows just fine.

The body classes seem to recognise the Android device just fine.

I am using yesterday’s nightly release.

EDIT: I have also tried adding custom mark up and using the config provider. In both cases using the desktop browser it all works as expected, but on the device it fails as above.

Ignore me, sorry, I was being a plum.