I encountered this:
I wanted to 'boolean add' those two shapes but was not able to get the right result.
The fill mode is set on winding as shown in the first image (add1.jpg)
but when I 'add' those two shapes I get the result as shown in second image (add2.jpg) (also same result if I would set fill mode on alternate or if I would press 'boolean divide')
So because the letter 'r' in the image is drawn this way, I think, is why I have this issue.
I know how I could bypass this but it would be a weird way :p
I would've expect from the 'boolean add' button to just merge everything into one shape.
I'm starting to use AD more and more, Awesome software!