The cache container is not located at the posted coordinates but is hidden within 1 mile.
This bonus physical cache is associated with the Adventure Lab Lynden - A Dutch Treat!
https://labs.geocaching.com/goto/7fe0062b-4e66-4a82-9672-5fc599a81302
Each successfully completed stage of the Adventure Lab will provide you with clues for the final coordinates:
N 48 5A.BCD W 122 2E.FGH
Note: You may need the browser version of the cache page to access the solution checker.
You don’t have to go to Europe to see an authentic thatched roof house — Lynden has one of its own! The best way to see it is to walk or bike the 3-mile Jim Kaemingk Sr. Trail as it goes right by it! (at the posted coordinates).

Thatching is the craft of building a roof with dry vegetation such as straw, water reed, or rushes layering the vegetation so as to shed water away from the inner roof. Since the bulk of the vegetation stays dry and is densely packed - trapping air - thatching also functions as insulation.
Reed has been used for centuries as a roofing material, especially on steep roofs of 45 degrees or more. Reed was readily available in water-rich Holland, while roof tiles had to be brought in from elsewhere. In addition, a thatched roof was relatively light, which was favorable because buildings were often built on a low load-bearing soil.

Where reed was available, it soon became the preferred choice; it is light, it ventilates, it insulates and it is durable. There was plenty of reed and straw to use and it was cheap.
In the past reed was mainly used to cover farms; nowadays reed is also widely used in houses in the higher price range.
The cache includes a Dutch souvenir for the first cacher to solve the mystery and find the cache container.
Congratulations to FullTimeRVers on the First To (Solve and) Find!