Click/Tap state shows fine in ionic lab (browser) but not on Android device

Hey folks, first post so bear with me on protocol and stuff.

New app working well in browser. When testing on Android device, clicks and page transitions work, but the button (or list item, etc.) never shows any state change to indicate the tap or click.

Any ideas? This should just work - no unusual code, very vanilla.

Device is a Samsung Galaxy, Android 4.4.2, which falls within the supported API levels for the version of cordova-android I am using:

"cordova-android": "^7.1.0",

Hopefully that markdown is clear - I see no “Preview” option here unfortunately.