Huawei mate 20 pro stereo sound?

I have had a huawei mate 20 pro for a long time but today when listening to music I noticed that the second speaker on the earpiece is not activated when listening to music.

The Huawei mate 20 pro has stereo sound? Or not

Or what do I have to do so that both speakers run while listening to music?

It doesn't look like I've found anything on various pages. (Idealo, https://www.inside-digital.de/handys/huawei-mate-20#datasheet-headline)

The mate 20 is shown on the link, but this is about the Mate 20 Pro and this model has stereo sound.