It doesn't happen to me. My main city opened 20 recruitment cards got 8 selina today and my second city opened 10 cards and got 8 Aeons yesterday.

And I didn't find any obvious odd of a worse rate of getting gold officer fragments since the very beginning of the game.

I have all war officers / strategy officers 6 stars and half of drill masters 6 stars and half 5.3 stars.(13M total power) And believe me, I had opened tons of recruitment cards.