Bottom speaker went silent at high column on iPhone 13

I have had an iPhone 13 for around 6 months. But only recently had I noticed that my bottom speaker went silent whenever the media volume is high (starting around 80%), leaving sound only from the ear piece.

Pausing the media for around 3 seconds and then replay does make it work again, but only for a few seconds before it went off.

The problem not only happens with media, but also with phone calls on speaker mode.

Does anyone have similar problem or have any idea why this is happening?