PropertyAction can't set properties inside Loader.item

Suppose a Component QML file with the following property and property changed handler:

property string blah
onBlahChanged: console.log("Blah has changed to", blah)

Now also suppose this QML file is the source of a Loader called "myLoader" and that loader owns some kind of animation containing the following:

PropertyAction {
   target: myLoader.item
   property: "blah"
   value: "new value for blah"
}

...the property "blah" will never get set and there is no warning output.

However if you use a ScriptAction instead:

ScriptAction {
   script: myLoader.item.blah = "new value for blah"
}

...the property is set fine.