So it will only happen some of the time when you are a bit slow in closing the levers.
Thus the reason for the "retard" callout.
I noticed in Tin Driver's video, the "retard" callout is made 3 times - is that because the aircraft they were on was 3 crew configuration?
At least Boeing still don't consider the pilots of their aircraft so stupid as to need to be reminded to close the throttles during the touchdown/landing phase!