BUG - Blitz Blast Kills Don't Register on Score

Has anyone else had a problem with kills from “blast” units not registering in their scoreboard kill count for blitz? I was playing around using Decimus with the suicide grunt and vortex abilities. The main idea was dropping a suicide grunt into an oncoming army and them immediately using vortex to pull all units to the center of the explosion. I learned 2 things. Firstly, this is a very cheap way to play the game. Secondly, it is incredibly devastating. I was able to destroy dozens of units nearly instantly at one time by using only 180 energy.

However, when the game was over I went to my scoreboard (after wiping out 4 separate armies using this technique) and found that it only showed I had killed about 10 units for the entire game. I then tried another game using this technique for nearly all of my kills (again, dozens destroyed) and the kill count showed a total of 2. Is there an issue with kills from these blast cards not counting towards the kill count on the leaderboard? Is it all blast cards in general or just when used in combination with a vortex ability?

Thank you.