Version:            (using KDE 4.2.2)
OS:                Linux
Installed from:    Ubuntu Packages

STEPS TO REPRODUCE:

1. Create a new to-do, with start date June 1, due date of June 2, with no time, and recurring every 7 days
2. Check the to-do as completed from the to-do view

EXPECTED RESULT:

The to-do start date would be adjusted forward in addition to the end date. There are a number of reasonable ways to do this, but the most sensible from my perspective is to keep the amount of time between start and end dates constant. In this example, after completion the start date should be June 8.

ACTUAL RESULT:

The to-do due date is updated to June 9, but the start date is still June 1.