I just bought a brand new Portofino Automatic IW356501 from an Authorized Dealer. After a full manual wind and left unworn, the watch stops after 17 hours. I repeated the 'experiment' and the result was consistent.
I'm pretty sure I've wound the watch fully because I could feel some resistance at the crown after about 20+ turns. Is there something wrong? The power reserve seems to be significantly under the advertised 42 hours.