It is the app, but the root of the problem is that the app you get from the google play store is not the same app you get from the download link on the instructions page.  Try downloading the APK from https://intuit.me/eswma (link found on https://quickbooks.intuit.com/learn-support/en-us/help-article/install-products/setup-use-warehouse-...), remove the install from the play store, and install the downloaded APK.  As per Lisalewisgale1'a post, I did this today, and the scanner now works.

Why Intuit would have a different app on the play store than the download, is beyond me, but that is the fix.