ios 10.3 bug or hardware defect?

[tertero]

i have iphone 7 plus ios 10.3.1, since 10.3 when i double tap home screen,bottom bar's color changing for a second. this happens only if one app open. Bug or hardware defect?

 

[Mefisto]

Happens on mine too. I'd go with bug, but as far as bugs go, this one's on the more tolerable end of the spectrum.

EDIT: If my homescreen wallpaper is all black (as it usually is), this doesn't happen.