Annoying beep on HUAWEI smartphone; how to disable?

Sometimes the device makes a 5-tone sound, it sounds like "Pling-Plung-Plung-Plong-Pling" on a children's glockenspiel (or g-d-e-f-g but with notes I was never good).

The sound sometimes comes at night without warning; but it is none of the adjustable beeps (such as SMS reception). He's probably connected to an online connection; In any case, he never came when the device was in flight mode.

Is that perhaps the signal when the battery is almost empty?

No.

Is NFC enabled?

NFC?

NFC is available for a wireless exchange of data over short distances (10-20 cm). If it is activated that can cause the sound (something I had with my HTC One M7 even then). Should be found under Settings -> More -> NFC.

Did you ever get this solved, phone is doing the same thing once moved, making 5 beeps, driving me mad!

my phon does it too. Couldnt find the source and its actullay way more than 5 bips. So annoying