The RightFingerTip in HandsCharacterBase is a ContinuousOverlapSphereComponent, unlike the fist spheres, which use a standard SphereComponent.
This component prevents the fingertip from passing through buttons without triggering them. The standard SphereComponent only supports continuous collision detection (enabled with "Use CCD"), not continuous overlap detection.
The Tick Until blueprint node runs once per tick from the Completed pin until it hits Break.