Time Slider range by YYYY

I have a time-enabled layer based on a field in the YYYY format. However, when using the time slider in the Geocortex viewer, the features in years at the bounds of the time slider range, do not show, or show incorrectly.

As far as I can see, this is because the time slider also uses time of day in the time extent. Is there a way to have the time slider only take the year into account?