Why Ogre::Matrix4::extract3x3Matrix and Ogre::Matrix4::decomposition doesn't return the same rotation?

Question

I have a Ogre::Matrix4, and I want to get the quaternion of this rotation. For this I use the extract3x3Matrix function then I am transforming this matrix in quaternion which give me one response. Then I am using the decompose function of Ogre::Matrix4 which give me an other quaternion. The 2 quaternions are different. How is it possible ?

Before applying the decompose function, I'm making sure the transformation is affine.

Ogre::Matrix4 car_T_tracker(    0.0124343,      -0.04752782,    1.010372,       -1400.69,
                                0.3480031,      -0.9485609,     -0.04890297,    647.4758,
                                -0.9497393,     -0.3481936,     -0.004690885,   1441.177,
                                0,              0,              0,              1);

Ogre::Matrix3 rotation_car_T_tracker;
car_T_tracker.extract3x3Matrix(rotation_car_T_tracker);

Ogre::Quaternion q;
q = car_T_tracker.extractQuaternion();

std::cout << "quaternion x : " << q.x  << std::endl;
std::cout << "quaternion y : " << q.y  << std::endl;
std::cout << "quaternion z : " << q.z  << std::endl;
std::cout << "quaternion w : " << q.w  << std::endl;

Ogre::Vector3 translation_car_T_tracker;
Ogre::Vector3 scale_car_T_tracker;
Ogre::Quaternion quaternion_car_T_tracker;

if(car_T_tracker.isAffine())
{
    car_T_tracker.decomposition (translation_car_T_tracker,scale_car_T_tracker,quaternion_car_T_tracker);
}
else
{
    translation_car_T_tracker = Ogre::Vector3::ZERO;
    scale_car_T_tracker = Ogre::Vector3::ZERO;
    quaternion_car_T_tracker = Ogre::Quaternion::ZERO;
}

std::cout << "translation : " << translation_car_T_tracker << std::endl;
std::cout << "scale : " << scale_car_T_tracker << std::endl;
std::cout << "quaternion : " << quaternion_car_T_tracker << std::endl;

quaternion_car_T_tracker and q are not the same quaternion but they should be.