indelible rests? What am I doing wrong?

Currently using Musescore for 4-part vocal (Barbershop). I seem to be encountering rests being inserted into the bass clef score in every measure, and can't seem to make them go away. This results in extra "whole rests" in every measure, even after entering all 4 voices into the score. I'm starting with the top voice, then 2nd, then 3rd and ending with bottom voice, before going back to enter lyrics. The only way I can make these rests not print out (or export to PDF) is by going back and, one-by-one, clearing the visible checkbox using the Inspector.

What am I doing wrong? Am I missing a step that is causing these whole rests to be indelibly inserted into the bass clef staff?