I used to have about 4500 Kills/2000 Deaths as Axis Sniper in Day Of Defeat: Source, but when I checked my stats a couple of days ago, those were deleted and my best stats are now 1400 Kills/940 Deaths as Axis Support. The Achievements are all still there, but the whole class/weapons statistic is messed up.
Same goes for Team Fortress 2. Acording to the Steamcommunity, I had 3 Assists as Engineer, 1 Defense as Soldier and 2 Dominations as Heavy, but in-game it is correctly displayed (5 Assists, 2 Defenses and 2 Dominations, all as Sniper).
Does someone else have this problem and/or has Valve stated a reason for this?

