I'm assuming this a result of the cutoff for each day. Since Guardians are present in many different time zones, we operate the cutoffs for days off of a single point in time.
The sum of the four games you listed places you at a 1.5 kill/death ratio, but there were three games a while back (but after the cutoff for the previous day) that you played before that logged a 0.44, 0.67, and 0.0 which were summed up under the same date.
Adding the four games you listed, plus the three games after the cutoff time, I reached 75 kills and 76 deaths, which is a 0.986 ratio which is rounded up.
Here are the three games that were included in your daily calculations.Game 1Game 2Game 3
Let me know if you have any further questions.