The API seems to show that your actual target multiplier was 1.14:

It's really weird that the frontend displays 1.13, but it's likely just a rendering bug. It doesn't make a whole lot of sense for Stake to try to cheat over $2 bets. Do you happen to remember what multiplier you were going for at the time?
I am guessing there could be some rounding out error? I mean not like there is an obvious and big difference, it is a small one so I am guessing there could be something regarding the rounding up error there, that seems like only plausible thing that comes to my mind. Obviously I am not affiliated with Stake so I can't talk on their behalf, mine is just a guess by some guy who doesn't even understand the concept 100% perfectly well, I am just assuming here.
The real results will come in when Stake takes a look at this and tells something, Eddie or Stunna has to say something about this. They even did the whole provably fair foundation thingy so they must be really certain about their provably fair situation, I checked mine all and they seem fine, but here we are with a proof of one guy not getting fair results, so they should make the announcement and defense against this.