Game History Graphs have incorrect data

I play Halo MCC with my friends every night, and we use the game history graphs in halowaypoint to track our scores.
It seems every now and then an incorrect game record appears in the graphs.
Here’s an example:

That graph is all correct, but the game on # 5 for the blue graph has the wrong scores(kills, deaths, assists etc).
Eventually, I was able to look at the network results from the graph, all the games it’s displaying are from April 4th. But that one game is from March 11th.
So an old game is being inserted and replacing the real game my friend played.

The way I got this was by looking at the JSON response when I load the page.
All the user had data like:
<ul class=“obj collapsible”> - GameId: 1, - Score: 23, - Kills: 23, - Deaths: 16, - Assists: 12, - Headshots: 5, - DateTime: “2016-04-04T04:18:40.405Z”, - MapId: 92, - LocalizedMapName: “STANDOFF”, - Won: true, - Medals: 11, - GameType: 0, - KD: 1.4375[/list]},

But the incorrect game had a record of:
<ul class=“obj collapsible”> - GameId: 1, - Score: 20, - Kills: 20, - Deaths: 15, - Assists: 9, - Headshots: 5, - DateTime: “2016-03-11T05:54:08.497Z”, - MapId: 82, - LocalizedMapName: “HIGH GROUND”, - Won: true, - Medals: 8, - GameType: 0, - KD: 1.3333333333333333[/list]},

As you can see it’s the wrong map, and wrong date too.

By the way, this is for Halo 3. I don’t really know if it happens for other games or not.