I had a strange thing with my lap times as well. I was driving at Tokyo, and right when I passed the finish line, I pressed start (i wanted to get the time at 0:00.000)
Anyway, I can't remember my time excactly, but what I saw was: 1:29.349 and when I looked to the right I saw that my lap already counted. So While I was in lap x, the 3 previous laps were: x, x-1 and x-2.
Not only that, but also the lap time of lap x was not 1:29.349, but it was 1:29.351.
lol so my lap was finished in the future, and it already counted!