Plugins is injected 2 times for namespace if it is extended class.

[AleksandrsKondratjevs]

When we creating plugin for source file and it is extended then plugin can inject same changes to both classes.

Example:
1.We have extended router.component.js in which we inject new component to render on specific route.

2. Create plugin to insert test route into source component.
   

3. Check router render array in a result.
   

[alfredsgenkins]

Should be fixed with this: 8a7483e