Statistics fundamentally broken

The statistics are a total mess.
The average K:D value in post game is quite different from the profile's value.
Also sometimes my K:D goes down even though I had a round like 52:0.
On other occasions it sky rockets for no good reason.
Sometimes the post result misses some kills or a death. Once it showed me ?:0 when I died one time.
The kills done with a specific weapon are off, two, especially for melee. It tells me I have done no melee kills, which just isn't true. The funny thing is that I even got the steam achievement for a knife kill, but still zero knife kills in game. (Btw the range of the knife is way to short. It should be easier to score a hit.)

Hey @Schmiddy,

Thanks for bringing this to our attention! Can you make a screenshot next time when you encounter again this issue?