Rear doors do not open from the inside when the car is locked

We discovered something peculiar today on our 2007. If the car is locked either front door can be opened with its inside handle. However, if the car is locked neither rear door can be opened with its inside handle. I looked in the manual and didn't see anything that described this.

This isn't the child safety lock. I verified that when the car is unlocked the child safety locks work as expected, and they make no difference when car is locked.