Just confirm to all of you that my problem was totally solved by fixing ground strap. It was loose, the mechanic forgot to fix properly after rod bearings replacement... and the "crazy crank issue" started.
In my case I was also convinced that it was a voltage issue during cranking. Because ONLY happened at starts, and only a few times. When the fail did not appear, it waorked perfectly.
If you see this:
Yo see the voltage during CRANKING, before, and after fixing the ground strap. The battery is the same, a new one. CLEARLY there is more than 1 volt "leaking" anywhere.
This peaks made the DCT "crazy". And not always. And of course, the stronger the battery is, the less you get the fail.
In the other picture, I messuared with a voltmeter between engine, and ground point (with engine ON, lights and conditioned air ON). I was able to see more than one volt. That meant the engine was not properly "grounded". After fixing the strap, I messure 0,02 volt at much.
I think it is a good idea to monitor the voltage in a "healthy car" during cranking, and compare to the "failing" car. At least in my case you can clearly realize the difference.
Now the car is working perfectly. I wonder what can happend if I stay long with the problem. May be the battery and the alternator can fail... or may be the ECU can be damaged... I donīt know.
Good luck!