oh I'm sorry mate, I didn't read that fully, I read the dots part but not the rest which is accurate. It doesn't really look like dots to me, it looks like the eraser function of a paint program was used to reproduce the right colour:
With error
Without
I used MyMobiler to get the screenshot so it doesn't really give a good indication but using paint to have a look at the cohesion and it was all one colour, a colour picker and bucket fill eliminated the wrong colour.
Apologies if you had tried all of this, I'm not a programmer but more a problem solver, hope that didn't offend you. I really do love your dialer, it has redial from call status functionality which even the minimal didn't have
EDIT: I should mention the graphic IS clean when the speaker button is pressed like this:
When speaker button is pressed
On call finish