Help needed please!!

I think the truss layout is 24" and the wrinkles are at 8' I conclude this by counting the shingle tabs. There are about 7-1/2 tabs or less, wrinkle to wrinkle. With metric shingle sizes, that would be eight feet. I had also considered that this might be wrinkles in 30# underlayment, but it is too regular, and more consistant with sheathing sizing, IMO. Of course, if like someone else mentioned, the sheathing was not nailed off very well, it could be both too. That could also account for the wavy surface in some places. I would not be surprised if this was barely nailed sheathing. In my years roofing, I probably crawled up onto well over a hundred roofs that the GC had proclaimed to be ready to shingle, only to find that the plywood was only tacked, or had been nailed off by amateurs who couldn't begin to hit the framing with their nails. Generally, I would nail it off and charge extra for the service before starting to shingle. Sometimes, in a larger project, the carpenters would still be around someplace and I could round them up to teach them how, and other times,when it was pure jerks building it, I would move on, and leave a message to call me for shingles when they got ready. Some shingle layers would just go ahead and apply. Point being - that it is not uncommon for some builders to let this get by. Another thought I had on this though, was that I have seen things like this a dozen times where it was the homeowner's error causing it. Couple of times it was because somebody had read or heard that by disconnecting the dryer hose and letting that heat go into the attic instead of outside, they could save on their energy bills, only to learn that repairing all that mold damage was mucch more expensive. Another guy had been leaving the atticc access hatch open to let the house heat go up there for some crazy reason