When testing relay components with IoC testing framework, firing of modelChanged event may end up in three situations:

1. The event is fired with correct new value; (correct behavior)
2. The event is fired with unchanged value; (wrong behavior)
3. The event is not fired at all. (wrong behavior)

The issue doesn't occur when,

1. The component is used outside of the IoC testing framework;

2. The exact same component works fine by replacing the relay grade with the corresponding non-relay grade, such as, replacing "fluid.renderRelayComponent" with "fluid.rendererComponent".