While on a FTF chase we parked nearby, (probably where you will park to get this). On our return to the geo-mobile (0ZG9R6) we noticed we could squeeze another cache in here. I checked out the location and found a suitable place for a cache and returned to the geo-mobile to grab a ready made container suitable for the hide. On my return to place the cache, I noticed the feature you will see if you find this and had a change of plans, so had to return to the geo-mobile once more for a different pre-prepared cache.
All will become clear once you find it.