Here is a jsfiddle to demonstrate the issue: http://jsfiddle.net/NfEgM/3/

When "set" is called on the "prop" property, the observer only fires if it is set with a new value. This is expected behavior.

The "computedProp" observer is firing every time, though, even when the computed value is the same. I believe this is unexpected behavior. The value is being recalculated because one of it's dependencies changes, but I think the observer should only fire if the actual value changes.

Is this a bug or intended behavior?