Transition can be stalled by Behavior

The attached file shows some unexpected behaviour.

Run under qmlscene/qmlviewer:

1. On a click, the console shows that the ScriptAction "Moving Started" part of the Transition is repeated rapidly until the Behavior animation is completed
2. Then the Transition runs to completion.

It would be expected that the two happen simultaneously. Perhaps in this case any change in opacity is causing a reset of the move transition. This appears to happen in other related areas, in some cases the transition stalling the Behavior.