Please upgrade the V4S Kiosk application to the latest version 2.4-88 or above, from Google Play Store or from the iTunes Store on to your Android or iPhones respectively.
This is a known issue.
When you click on Roster button you see "Undefined Undefined" for a few seconds until the V4S Members page gets loaded. Once the Page is loaded "Undefined Undefined" disappears and comes up with V4S Members List.
You see one row of "Undefined Undefined" for each Shift, so if there are 3 shifts you see Undefined Undefined in 3 rows.
This is a known issue and will be fixed soon.