mobile

I've noticed since Lollipop that the phone's system sounds (e.g. when tapping to launch an app) are sometimes faint, sometimes at normal volume. I have all volume sliders at maximum, and I've tried toggling muting on and off. I've already factory-reset the phone since Lollipop.

What often happens is that an initial tap or two sound faint, but subsequent taps just a second later are normal. It's a bit annoying. Is there anyone else who's encountered this, or knows of a solution? (I'm using Google Now launcher, if that matters.)