Why are homescreen icons bouncing? My wife and I just got new Essential phones running Android 9 (Pie.) On my wife's phone, the docked toolbar icons at the bottom of the homescreen bounce every few seconds, as if they're asking for attention. 

She didn't install any weird UI tweak to force this. What is the purpose of the bouncing?
I went back into settings, system, gestures, and toggled "swipe up on home button" off then back on.