A THREAD FOR NEWCOMERS!

I read somewhere that the Sphere of Vulnerability counters the magic resistance skill, including that of Thorgrim. At the same time, there was a situation: with the sphere equipped, Armageddon was cast, and black dragons sometimes took damage, and sometimes they didn't (i.e., the resistance clearly triggered). Another point. In the same game, the artifact Spirit of Oppression didn't work; the overall morale was -2 (creatures of different races + undead). If I removed the troops, leaving the morale at 0 or +1, it suddenly started working... Why could this have been?