Sump Pit Bone Dry After Running Every 5 Minutes, How?
You should be concerned with wanting to be concerned about things that are not problems, if you're going to be concerned about anything, here.

Not that difficult - the local-to-your-sump-pit groundwater source level has receded below the floor of the sump pit. The groundwater has moved to refill local groundwater stores and is no longer high enough to enter your pit.