Duration not updating when changed from standard hours

Summary:

Duration not updating when changed from standard hours.

Content (please ensure you mask any confidential information):

When we change the Start Date Duration from someone's standard hours, the Duration below does not update and the data that actually gets submitted is the below duration (6.4 hours).

From ESS Add Absence:

From ESS Existing Absences:

When we click on the Show individual dates, then the Duration 6.4 Hours disappears and we're shown this:

And when I save again, the hour of 1 seems to hold:

Is this working as expected or should the duration be changing based on what is entered in the Start Date Duration in the first screen shot above?