Repro:
1. Download package and project at: https://github.com/Unity-Technologies/InputSystem
2. Go to scene at: Assets -> Demo ->SimpleDemo -> SimpleDemo
3. Enter Playmode
4. Hold down left mouse button for a short time, then let it go
5. Observe how long the shooting lasts

Actual: The "duration" value is much longer than the actual time

Note: When using callback function like this:
controls.gameplay.fire.performed +=
ctx =>
{
if (ctx.interaction is SlowTapInteraction)
{
StartCoroutine(BurstFire((int)(ctx.duration * burstSpeed)));
}
else
{
Fire();
}
m_Charging = false;
};

The value for duration is calculated though time and startTime. However, the startTime for callback function is always 0, which makes the duration value much larger than it is.