Reach PC Multiplayer Stats not counting correctly

So, I startet playing Reach on Steam yesterday and linked my Xbox-live Account to the Steam version to have all my stats from early 2015 back to my account (that was the last time I played MCC on Xbox). My stats were approximately 6300 Kills and around 3100 Deaths or so. I checked the stats yesterday before playing the first game in years and it was definitely a slightly better K/D Ratio than 2. I do not know the exact stats anymore because I already played like 10+ hours since yesterday. I check my overall multiplayer career stats after every game and I realised that something is weird. Right now i have 7400 Kills and 4000 Deaths (approximately), but the thing is, of all the games I played up until yesterday I had not even once a negative KD, the worst I had was 10 to 10 game and most of the games I played I had a 3+ K/D ratio. 95% of the games a 2+K/D ratio at the minimum, so my K/D ratio should not get as worse as its now. Especially in the last games I had scores like 42-6, 46-9, 33-7 and so on but I feel like everytime I check my stats my K/D ratio gets worse. I care about my stats a lot so thats why I can remember all these numbers. I have to add that the career stats do not update immediately, maybe like every hour or so. So my question is, if there are any other people who think something is counted incorrectly in the career stats?

Exceed

Just a note: My stats from Halo Reach, which I can see here on Halo Waypoint prove that my stats must be way better. Also my overall MCC Multiplayer stats here on Waypoint differ heavily between here and ingame. Here it says I have 8270 kills and 4280 deaths.