Noticed this for a long time working with BB but since you have opened this community I figured I might as well ask about it.
When you add top (for example) padding to a row in BB on Desktop, and leave the mobile and tablet top padding untouched / at 0. The padding you applied to desktop will still show in mobile and tablet when you view the website in BB preview mode either in the BB theme or in the Customizer viewer.
It’s a little annoying and would be nice if that could get fixed.
The workaround I usually do is I simply add margins to my columns in the row instead.