Its not just DBM missing borders. The icons below your player frame have 10 sides missing and the small green rectangle on your Qusemap has the bottom missing. (Possible fix for DBM is keeping the scale at 1)
I also would get the double think borders on my Raven buff and debuff borders. It just takes a bunch of fiddling around with size and spacing to find the right setting to not have a single icon with one. (I don't know if this only happens on larger res screens and not on say 1080 but it can get annoying I know)
Also I'm my experience the missing border on a side is from changing the scale to size things instead of just its size value.