Isis itself violates an important tenant of Islam in and of itself, the tenant of non-violence. By violating this tenant it memes them not true practitioners of Islam, and it means that they should not have formed the wall. This is only one way in which the wall of Sharquat was a violation.
Just as our politicians talk a good game without living up to it, so do the leaders of ISIS. They don't really care about the Tenets of Islam, they want control. Religion is the best way to control people, so it makes sense to use that avenue to bring your followers to heel. This guy was doing what any coward does when faced with capture, he tried to run and give himself the best chance to escape.
Islamic scholars are condemning ISIS for violating tenets of Islam. Are you referring to the capture of a governor in female dress? Or the requirements that women wear modest dress and have been tortured for failing to do so in the eyes of ISIS? Several Islamic scholars have commented that it's forbidden to kill the innocent, torture people, and disfigure the dead. ISIS/ ISIL have done all of those, and they are contrary to how most scholars interpret Islam.
Yes, ISIS's Wali of Sharquat violated a Tenet of Islam because ISIS does not represent the religion in any way. It is simply a terrorist organization meant to create fear and death across the world. They do not uphold any major religious text and they simply want people to fear them.