The grudge just keeps getting bigger.
It had been some time since Cercis Flower was within the Princess Star Domain, and the Iron Armor Battle Group had been up to no good for a while, so some evidence had been collected against them, and it was eventually given straight to Holy Terra, leading to an armed conflict with the Iron Armor Battle Group.
Cercis Flower couldn't resist the far larger scale of the Iron Armor Battle Group, to say nothing of the fact that three other Battle Groups were standing with Iron Armor.
So, they began to shake people up. It was at this stage that Phoenix, who had good relations with them, was swayed to join their side.
But at this point, things were actually not too bad; if you turned a blind eye, the situation could perhaps be passed off as not amounting to civil war.
However, Holy Terra's subsequent actions exacerbated the situation.
The Empire Government certainly did not like what the Iron Armor Battle Group was doing.