I went to check the stats of my Infiltrator (Endoria) via the app (app.playphoenix.online) and found that I am missing all player kills. Since I have killed players and have done so already a few days ago, it makes no sense for my stats to show zero kills, zero solo kills.
[EDIT] Just for extra context, I used to have a Champion named Endoria during Season 1 and I deleted her when I created this Infiltrator. I have no idea if this could cause issues, so I just put it in here.