Hero digger

Here's the situation: on the first day, I found a caster hero with an army of 9 knights and 4 gargoyles. On the second day, the same hero had an army of 6 knights and 2 gargoyles. P.S. I made the digging site cost 2500. The first time, I set it to 5000, and the second time to 2500. And here's the sad result. I'm curious what could be causing this.