I have never encountered this issue in the past but the past few days I having a hell of a time with my A20. It all started with the introduction of the progressive elements. The A20 is my favorite tank, so naturally I wanted to display my progressive elements on my tank, but after a few day I encountered a bug where they simply will disappear after a game with more and more frequency, its gotten to the point where they disappear the moment I load into a game. The worst part is they do not go into my Depot, I have to rebuy them. Now my actual camo has disappeared and again, it is not in my depot. I don't know if this is an issue specific to the A20 but its the only one I've encountered the issue on.
TL;DR
My A20s progressive elements and now camos are disappearing