Please offer some advice.

Here's the situation: in a campaign, on one of the maps, enemy castles produce units at an incredibly fast rate. If you capture an enemy castle on the first day, the number of units isn't alarming. However, after a month of gameplay, there are 55,000 units available for recruitment in these castles. Naturally, the "owners" can't afford to hire them, so it doesn't hinder gameplay, but I'd like to understand the reason for this rapid reproduction. In the map editor, I deleted these cities and placed new ones, but it didn't help – there are still tens of thousands of them. I'm seeing this for the first time...
How is this organized on the map?