Posts from Daleb’s Fireball

According to the ability description, the Delab ballista should additionally deal fire damage of 20+20*(2+hero level/5). However, for some reason, starting from level 1, it only deals 1 unit of fire damage. At the same time, the damage dealt to the selected target is greater than what is shown for the ballista, i.e., it is possible that the additional fire damage exists, but it is not area-of-effect; it somehow merges with the ballista's damage. Also, the fire sphere only deals 1 unit of damage, and neutral creatures seem to ignore the racial summon, which might be causing this bug.

It's not +2, but -2. Starting from level 6, the ballista deals 20 damage with a fireball (rounded up), and it seems the damage from the fireball doesn't carry over to the ballista's damage at lower levels. In what sense do they ignore the racial summon? Do they not attack summoned creatures? If so, that's how the AI is configured.

and the neutrals seem to ignore the racial summon, which is why this bug might occur?

In version 3.0, neutrals ignore summoned demons if you manage to reach the actual units.