tf::TransformListener gets wrong tf

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Hello,

TL;DR tf::TransformListener gets a different transform than shown in RVIZ

I am having quite a strange problem. I am using a rosbag file to playback recorded data and I am adding new transforms and using them while doing that:

rosparam set use_sim_time true
rosbag play 2016-09-12-14-51-41.bag --clock

The transform is published with a python node, where the origin is static (defined with cfg-values) and the rotation is coming from the values of an IMU. The interesting part how the tf is published should be this (in the callback of the IMU subscription):

  br = tf.TransformBroadcaster()
  br.sendTransform((frame_offset_x, frame_offset_y, frame_offset_z),
               quaternion,
               rospy.Time.now(),
               frame_child,
               frame_parent
              )

With the following values:

  frame_offset_x = 0
  frame_offset_y = 0
  frame_offset_z = 1.2
  quaternion = rotation of the IMU (only around the x and y axis)
  frame_child = level_laser_2
  frame_parent = base_footprint

The created Transform in RVIZ looks like expected. It's 1.2m above base_footprint with some rotation on top. In the picture, the Fixed Frame is set to "base_footprint"

However if I lookup the transform in a ROS node using the tf::TransformListener I get a different result:

#include <tf/transform_datatypes.h>
#include <tf/transform_listener.h>
...
  tf_listener_ = new tf::TransformListener( ros::Duration(10) ); // in the constructor
...
void callback( const sensor_msgs::PointCloud2Ptr& cloud_in ) {
  ...
  if ( tf_listener_->waitForTransform(tf_target_,
                                      cloud_in->header.frame_id,
                                      cloud_in->header.stamp,
                                      ros::Duration( scan_time_ )) ) {
    tf::StampedTransform transform;
    tf_listener_->lookupTransform(tf_target_,
                                  cloud_in->header.frame_id,
                                  cloud_in->header.stamp,
                                  transform);
    ROS_INFO("%s %s -> %s\tat%lf", node_name_.c_str(),
                                   cloud_in->header.frame_id.c_str(),
                                   tf_target_.c_str(),
                                   cloud_in->header.stamp.toSec());

    tfScalar tf[16];
    transform.getOpenGLMatrix(tf);

    ROS_INFO("%s\n"
             "/ %lf\t%lf\t%lf\t%lf \\\n"
             "| %lf\t%lf\t%lf\t%lf |\n"
             "| %lf\t%lf\t%lf\t%lf |\n"
             "\\ %lf\t%lf\t%lf\t%lf /", node_name_.c_str(),
             tf[0], tf[4], tf[8], tf[12],
             tf[1], tf[5], tf[9], tf[13],
             tf[2], tf[6], tf[10], tf[14],
             tf[3], tf[7], tf[11], tf[15]);
  } else {
    // display error here 
  }
  ...
}

The output of this is:

[ INFO] [1473756806.521699009, 1473684710.202103154]: /level_laser_velodyne:  base_footprint -> level_laser_2 at1473684709.395050
[ INFO] [1473756806.521764836, 1473684710.202103154]: /level_laser_velodyne: 
/ 0.997645  0.001908    -0.068567   0.002741 \
| 0.001908  0.998454    0.055557    -0.002221 |
| 0.068567  -0.055557   0.996098    -0.039822 |
\ 0.000000  0.000000    0.000000    1.000000 /

But it should be something like:

[ INFO] [1473756806.521764836, 1473684710.202103154]: /level_laser_velodyne: 
/ R R R 0 \
| R R R 0 |
| R R R 1.2 |
\ 0 0 0 1 /

Does anybody know what I am doing wrong?

Thank you for your help, Tobias