Have you ever seen a gutter drain on a roof This is actually a common practice. But just because it is common, does not mean it is right.
When you drain a gutter onto a roof like this, it causes that section of roof to get more water than other sections, causing premature wear, and possibly leaking.
This is a very common building practice that we see as home inspectors, but one that always makes us look a little bit closer.
Remember, just because it is “allowed”, does not mean it is the right thing to do.
The simple fix is to fit a leader so that it drains to the gutter below it.