Well unless it is low morale issue, this just supposedly mean, yusuf is genious generals... maybe he used avalanche to destroy your forces? XD
Anyway... lol, don't use more artilery than infantry!!! It will mean your artilery will be destroyed during shock phase, and you don't want this to happen. Artilery need to be in second row!!!
Morale was excellent, all the artillery was meant to be delivered to a bunch of sieges. I regarded the revolt as just an distraction
One would assume that 8 infantry units would be enough to shield the artillery from 1 enemy regiment though.