The cache IS at the posted coordinates. But you must meet the challenge qualifications before you claim your find.
We love Letterbox Hybrids. Maybe not as much as Virtuals or Earthcaches, but they are up there. This is a simple challenge. To qualify, you must have found a letterbox published each year since the oldest letterbox hybrid in Maryland, GCMFNH, was published. That means a letterbox hybrid published each year for the years 2005 through 2021. I qualify with finds published each year starting in 2001, but since the nearest 2001-published letterbox hybrid is in Massachusetts, I wanted to make this challenge attainable for the Maryland locals.
The cache is rated given the difficulty to get all of those finds. The challenge cache itself is probably a D/T of 1.5/1.5. You may sign the log any time, but only claim the find when you meet the requirements. BYOP.