To reproduce:

1. open a new project
2. select the main camera and add a component - new script - java scipt - the default name is: NewBehaviourScript
3. add two more java script components in a row, notice that the default names of those scripts are NewBehaviourScript1 and NewBehaviourScript2
4. add one more component this time a boo or c# script - the default name is NewBehaviourScript3
5. add one more boo or C# and the default name goes back to NewBehaviourScript
6. the default names are broken from now on