Hi,
I have noticed this before a couple of times, but with version 5.5.7 it has become almost impossible to work with the builder (it happens like 1-2 times per 10 minutes while actively building layouts).
When I add or change margin / padding settings on some columns and select any other element, then the margin and padding settings are copied also to another column within same section. This messes up the layout totally. Sometimes it's difficult to notice this if the layout is complex and margins smaller, so it appears sometimes later.
This happens with different browsers like Chrome and Firefox.
Thank you for looking into this!