I notice it too, and it's because the music is extremely low bitrate - usually 48kbps, but sometimes as low as 32. It's HE-AACv2 - not as good as Opus, but clos

I notice it too, and it's because the music is extremely low bitrate - usually 48kbps, but sometimes as low as 32. It's HE-AACv2 - not as good as Opus, but close. Its characteristic artifacts include destroying transients, like your hi-hats.