I had problems with openlayers on android mobile. It was not finding the features. I found the pixel being returned had the wrong pixel value. I put this into codepen to be run on the debug mode. when ...

On Android 4.4.2 or 4.0.4, use the default web browser (with default webview) or App with webview to navigate to for example https://openlayers.org/en/main/examples ...