On Android, it appears android.graphics.Region (which is used internally for clipping against a Path) is not anti-aliased. This means if you set a clipping path that is not rectangular, such as a rounded rectangle, then the interior clipping path will have jaggies.

My workaround for my rounded rectangle clipping with a border is to draw the border after drawing the interior, and allowing the stroke to be wide enough to cover the jaggies. But IMHO it’s a kludge.