Gradient Map problem when I do B&W conversions

Something seems to have changed in the way handles (Gradiant Map Tool) work in the latest versions of Photoshop. I use gradiant Map for black and white conversion and in my workflow, I add some handles using the ALT-Click key to clone a tonality on the gradient line and then I move those handles left or right to bring modifications. Now, whenever I click a freshly created handle wanting to drag it, its tonality changes automatically which I do not want.    

I've tried different key combinations but it changes the handle color everytime.  It is now useless for me! 

Any idea?  Thanks!