back to this.
After around 400 miles with the brand new brake master cylinder, the same behaviour developed. The free play on first application of the front brakes is too much, after quick release and reapplication of the lever, it goes to normal.
So I took the bike back to the dealer as well as the "old" brake master cylinder to be reinstalled. The dealer's owner was disappointed and asked me to leave the bike at his place for the winter, so he could investigate the issue more thoroughly. He's not happy with not being able to sort this out for me. And since the bike is unregistered during the winter, it's irrelevant to me where it hibernates.
So, I'll leave this post sleeping until the beginning of March, when I'll pick up the bike and see if there's anything improved.
Meanwhile, if any of you guys has any suggestion, I'm all ears.