Just to give a brief background:

I've been playing the game since 2012 on RU server and since 2014 on EN server. That's me, over a decade, punching infests every single day, on 2 servers. Lately, I'm playing on EN server only.

Now, with the issue:

I know how infests work and what force I should expect to send and receive for each time I hit them. I've been doing infests for over a decade, without inconveniences, except for 3 times, when I lost majority of my army. All those 3 times, I had purchased troops and crystals. The most recent purchase was around a week ago.

Usually, I use infests to gain army from tournament rewards, so my army keeps growing, but all 3 times I bulk purchased army and crystals with cash, I noticed, that infests sucked up majority of my army, without returning nearly as much, over the span of several days.

P.S. It seems to me, that there's an algorithm, that, once it determines, you're willing to use real life cash, it burns your troops, so that you spend more and more. I can't explain what has happened to me otherwise.

P.P.S. Can anyone explain what's the cause of this? Because, my version of the possible explanation highly discourages me to make any ingame transaction in the future.