The cache is not at the posted coordinates.
This is the bonus cache for the Adventure East of Snoqualmie Pass Adventure Lab. I hope you enjoyed the journey, visiting all the locations, and maybe even found some new places to explore.
Keep in mind: to find this bonus cache, you must complete all stages of the Adventure Lab first. To get the coords for this bonus cache, take the info from all the stages and plug it into this formula:
N 47 AB.CDE W 121 FG.HIJ