If you look to the left of the center line, you can see the shingles curled up, I think they are cut too close to the valley itself, I was unable to enter the attic because of access issues.
Were you able to lift the shingles up to see the valley?
California cut valley,
Scott has the cut valley info. That does look like an ordinary cut valley though.
This would be a California cut…imo
Would there not be a weave under the cut side?
It looks cut on both sides to me. Like a tight open valley.
It could be that the so called roofer cut the shingles in place with a knife after he laid and nailed them and cut into the underlying shingle, but I am not there to verify, and no there is no weave under the cut side.
Absolutely what is shown here. Very common for shinglers in my area to cut the valley after overlapping. In my experience, they would chalk a line and cut the valley. It’s a cheap way to do it. I will say, I believe it is supposed to be cut 2 inches from the center of the valley.
That would explain it.
That’s the key right there to answer the question. And if the cut valley would have been 2" off-center, it would answer your question also as if it was done right.