Flashing seams not sealed?

Hello. My roof changes pitch about half way down the roof (from about 8/12 to about 5/12). My roofer placed flashing along the line where the pitch changes. He used a few different sheets of flashing. But he did not place any sealant in the seams between different sheets of flashing. I can understand if no sealant is used when gravity directs the water perpendicular over the seam (like in a down-sloping valley). But in this case, gravity will cause the water to flow PARALLEL with the seam. See the pic attached. You can see there is already a pine needle under the seam. In more time, I could imagine more of those collecting, and with maybe a strong wind allowing water to move horizontally causing a leak. What is the standard in this situation ? Should these seams be sealed ?

No, they should be overlapped 6". No sealant required

Why in the world did he install flashing in a standard pitch change? He could have run comp right through if he paid attention to where the courses landed and nailed appropriately.