Changes to View Not Saved

I have added a new view to a graph extension, my expectation is that changes made to it would be persisted during the normal Save process. However, I am noticing that after the updates

I do not believe my call to TimeActivities.Cache.SetValueExt is actually updating the cache. 

Why would this be?

namespace GPGeneral.CR
{
    public class TimeCardMaint_Ext : PXGraphExtension<PX.Objects.EP.TimeCardMaint>
    {
        public static bool IsActive() => (true);

        public PXSelectJoin<EPTimecardTask,
        InnerJoin<CREmployee, On<CREmployee.defContactID, Equal<EPTimecardTask.ownerID>>>,
        Where<CREmployee.bAccountID, Equal<Current<EPTimeCard.employeeID>>,
            And<EPTimecardTask.ownerID, Equal<Current<EPEmployee.defContactID>>,
              And<EPTimecardTask.weekID, Equal<Current<EPTimeCard.weekId>>

                  >
                >
            >> TimeActivities;

        protected void _(Events.FieldUpdated<EPTimecardDetail.timeSpent> e)
        {
            if (e.NewValue == null)
                return;

            var nTimeSpent = (int)e.NewValue;
            var tmDetail = (EPTimecardDetail)e.Row;
            foreach (EPTimecardTask tmTsk in TimeActivities.Select())
            {
                if(tmTsk.NoteID == tmDetail.RefNoteID)
                {
                    var newClockOut = tmTsk.StartDate.Value.AddMinutes(nTimeSpent);
                    TimeActivities.Cache.SetValueExt<EPTimecardTask.endDate>(tmTsk, newClockOut);
                    TimeActivities.Cache.SetValueExt<EPTimecardTask.uistatus>(tmTsk, ActivityStatusListAttribute.Completed);
                    //tmTsk.EndDate = newClockOut;
                    //tmTsk.UIStatus = ActivityStatusListAttribute.Completed;
                    //TimeActivities.Update(tmTsk);
                    break;
                }
            }
        }
    }
}