[tinner666]

Don't ya just love the stuff? Of course, not clipping the tops is a shortcut that should always be avoided, but isn't.
THough th eroofers never felted the house, THAT issue isn't what caused the leak. The leak was caused by not clipping the tops, AND not leaving an open channel against the wall for the water to flow freely. :whistling:

 

[tinner666]

Another pic. See the water trails beside the channel? This is the work of Hacks!

 

[tinner666]

To use channel flashing correctly, cut the tops back to the edge and leave a water channel along the wall!

 

[tinner666]

In the picture with the old shingle, you can see the dust, pollen, and other crap collecting along the wall as it waits to work itself under the shingles and clog the channel.
In the picture with the new shingle, you can make out the 1" wide channel along the wall. It's not a perfect system and will never compete with step flashing, but it can work.