App changing notification sounds

I posted earlier about not receiving notification on the app of movement. Today I checked my sounds to notify. They had changed from the ones I had previously set! I set up DEFAULT - Typewriter-typewriter for all notifications. Today after receiving no notification of the postman I checked my settings. It read DEFAULT - Typewriter - Bongo. Bongo is a Huawei notification noise. Why is this happening? It seems to stop any notifications from being pushed as it cannot decide what noise to use. Any ideas? Many thanks.