[Tuidjy]

The manual suggests that when two big armies move against each other, the
larger is somewhat likely to push back the smaller one, and invade the
enemy province. I'm playing Ermor in a test game, and moved four 500+
armies against Ulm. Not once, but four times out of four, my hordes were
pushed back by armies numbering in the twenties.

Can one of the developers look into it? I would not be surprised if a
comparison operator is inverted somewhere. Or maybe undeads' numerical
superiority does not count.