That wouldn't surprise me at all. It's well known that there is a "test track" in the skies over the Pacific Northwest. It extends well over the pacific yet also covers eastern Oregon, up through washington and well out to sea.

There are times when they leave the contrails and it's not an Alaska to California flight either, nor anything coming in from Asia.

They fly two test tracks. Think of a rectangle with rounded corners, each has its own designation and only certain aircraft fly certain tracks.