You're not supposed to have two steps with the same name at the same level in a QB configuration.
But I just discovered that, if a configuration inherits a step from a parent, you can create another step named the same, at the same level, in that same configuration.
The two steps will then appear as override, and if you modify one, the twin will get the same modification.
After that, if you try to create a third step with that same name, QB will detect that the step already exist and prevent you to do so, the problem seem to only happen when the same named step is inherited