I got the D120 Fat Stack tanks as my anomoly reward after 30 days of playing every day to see what it was. Added it to a deck and used it single player. Got a second as a multiplayer reward after a battle a day or two later, not sure why. Went to do single player today, and there was a symbol by my deck. Went into it, 1 tank was there, couldn't add the second. Exited, went back in, and now there's none and my deck has 29 count.
Update: Closed the game, went back in. Symbol is still there. 1 tank is back. Second is not selectable. Used the "owned and unowned" filter. It says I have -1 (negative one) D-120 Fat Stack tanks. WTF.