VS Client only - adding / updating time entries on the Time Tracking Tab does not update the time spent attribute

Using RTC 4.0.1 with the VS Client and Formal Project Management (FPM) template, found that VS Client only - adding / updating time entries on the Time Tracking Tab does not update the time spent attribute.

steps I use:
1 - create a FPM PA
2 - create a new defect - set yourself as owner
3 - save
4 - time tracking tab: add some time entry - save
5 - go back to the overview tab
expected: read-only time spent attribute's value is computed from time sheet entries
observed: read-only time spent attribute's value is not set

Is this a defect?