Safari and Chrome play alert sound on URL load every time

[jackcanterbury]

I can't figure out why Safari and Chrome play the OSX system alert sound ("Funk") every time when I hit the "return" key to load a new page after opening a new tab and entering an URL. It is fine with no alert sound when I just click on some links and redirect it to other webpages.

This problem only appears on my 2016 MBP, but not my MBA2012 and MB2015. Very strange and annoying... may I know if anyone has encountered this issue? Many thanks for help..