It's a pretty minor thing, but I guess I'm being pretty pedantic here.....anyways;
When a player/CPU double faults, it doesn't take into account of the 'Points won on 2nd serve' part of the stats. Instead it adds onto the 'Return Winners' stat for the opposition.
Simple example -- starting the match, playing the first point on your serve:
Take into account of 'Points won on 2nd serve'. It's 0/0 = 0% as expected. You serve first....you double fault. Okay so first stats page is right -- ie. Double Fault tally is 1, then the opponents 'Points Won' is 1....all well and good. Then the next page on the stats -- 'Points won on 2nd serve' is still 0/0 = 0%??? And opponent's 'Return Winners' is 1??? I think it should be 0/1 = 0%....and I'm pretty sure Return Winner doesn't count because the opponent didn't do nothing to return it, rather it's the player's own service error to lose the point.
I'm not sure if you've come across and have mentioned this or not, and likewise to fellow players (or similarly, you've corrected this already with a new patch already available). Apologies in advance in this is the case.