Thank you for your answer gr5,
I am going to aboid the test at Minimum travel: 3mm (Retraction - Expert config), now I think that it is just to much.
I am thinking that maybe the fillament is getting flat and loosing grip because of the speed that I am using,
The print speed is 50 mm/s, but because of the geometry of the part I have to lower the speed down to 20%, do you think that the speed reduction my cause that the fillament gets just too much retractions in the same area.
Other thing that I did was to change the speed from 20% (Material Flow 120%) to 85% (Material Flow 180%), I think that my afect also the fillament flatness;
I am thinking on doing the changes more gradually, and run a new test;
What you guys think.