While browsing the map, I encountered an unpleasant bug. I used a mine as a sorting point for troops, leaving units in the mine's garrison. Suddenly, the mine changed its flag, and demonic stacks appeared there, while the units I left became my opponents. The mine's defense turned out to be reinforced.
There are significant problems with sorting diverse troops on the map. Leaving them in mines is not safe, and the Academy's castle garrison is one-sided. You can place troops in it, but you can't take them back out. Using a single hero as a holding area for unwanted units is not very convenient.
If reinforcements were sent in separate batches to different castles, it would eliminate the need to distribute units. But as it is, you can't do without a sorting point.