It can be embarrassing and a bit rude when your phone goes off at an event where it should have been put on silent, such as in the movies, or in a meeting, or in class. However WhatsApp for Android has been giving users a bit of problem in that regard as it seems that there was a bug that allowed the app to send out audible notifications even when your phone has been set to Priority mode.
The good news is that it looks like an update has been issued where the app will no longer send the user audible notifications when the phone has been placed in Priority mode. Prior to this, users had blamed Google for the bug, claiming that because of the changes Google made in Android 5.0 Lollipop, it kind of messed things up.
However Google back then claimed that everything had worked as intended, and that it was up to developers to ensure that their apps would play nice with the latest build of Android, which we guess WhatsApp has finally gotten around to addressing. For those who have upgraded to Android 5.0 and were annoyed by this bug, you can grab the latest build of WhatsApp from the Google Play Store.