Adding an FSM to my project locks down Y mouse axis[NOT RELATED]

[PolyMad]

I know it sounds absurd, but it seems what's actually happening.
I have my project, the character (standard from Unity) works well, but when I add an FSM, to another prefab, the Y axis are then locked: I can only look left and right.
I really can't understand how this is even possible.

I opened a thread on the Unity forums, because I am not sure if it's PlayMaker the trouble cause or Unity BETA itself.

http://forum.unity3d.com/threads/stupid-problem-with-rendertotexture.400283/

[PolyMad]

Just found another inconsistency: one of my prefabs, the first to which I added and FSM, has now a child object to it that I never added.
It's named exactly like the prefab, and when I add it to the map, I only see the parent object, the child object only shows up in the project folder, it disappears when the prefab is added to the map.
Note also that I copied the same FSM to other 3 prefabs, modifying it slightly, and the other 3 prefabs do not show the same problem.

This child object is a script: PlayMakerFixedUpdate. Removing the script from the object doesn't remove the child object.

[PolyMad]

OK I don't know if this is PlayMaker related, but I tracked down the problem to the second camera.
Despite the second camera having no script attached at all, and despite the fact that I didn't modify the Unity character scripts at all, now this configuration with two cameras in the same scene won't work.
I removed the second camera, and the mouselook works now, so the chances that PlayMaker is involved are thin now.