Turtlebot3 vs Turtlebot3 + Kinect: good vs bad navigation

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So this is the situation I'm dealing with: If you look at my previous posts you can see different problems that I got to finally mount a Kinect to my TB3. Now I want to use rtabmap to do navigation,mapping,localization. At the bottom of this post there is the question.

So, after the commands I use there are the URDFs of my tbots:

roslaunch turtlebot3_gazebo kinectbot3_race.launch model:=waffle_ki (_ki stands for kinect, _pi for the standard waffle_pi base)

To start gazebo in a world map made by me

roslaunch rtabmap_ros demo_turtlebot3_navigation.launch model:=waffle_ki

it starts rviz and rtab

Standard:

<?xml version="1.0" ?>
<robot name="turtlebot3_waffle_pi" xmlns:xacro="http://ros.org/wiki/xacro">
  <xacro:include filename="$(find turtlebot3_description)/urdf/common_properties.xacro"/>
  <xacro:include filename="$(find turtlebot3_description)/urdf/turtlebot3_waffle_pi.gazebo.xacro"/>

  <link name="base_footprint"/>

  <joint name="base_joint" type="fixed">
    <parent link="base_footprint"/>
    <child link="base_link" />
    <origin xyz="0 0 0.010" rpy="0 0 0"/>
  </joint>

  <link name="base_link">
    <visual>
      <origin xyz="-0.064 0 0.0" rpy="0 0 0"/>
      <geometry>
        <mesh filename="package://turtlebot3_description/meshes/bases/waffle_pi_base.stl" scale="0.001 0.001 0.001"/>
      </geometry>
      <material name="light_black"/>
    </visual>

    <collision>
      <origin xyz="-0.064 0 0.047" rpy="0 0 0"/>
      <geometry>
        <box size="0.266 0.266 0.094"/>
      </geometry>
    </collision>

    <inertial>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <mass value="1.3729096e+00"/>
      <inertia ixx="8.7002718e-03" ixy="-4.7576583e-05" ixz="1.1160499e-04"
               iyy="8.6195418e-03" iyz="-3.5422299e-06"
               izz="1.4612727e-02" />
    </inertial>
  </link>

  <joint name="wheel_left_joint" type="continuous">
    <parent link="base_link"/>
    <child link="wheel_left_link"/>
    <origin xyz="0.0 0.144 0.023" rpy="-1.57 0 0"/>
    <axis xyz="0 0 1"/>
  </joint>

  <link name="wheel_left_link">
    <visual>
      <origin xyz="0 0 0" rpy="1.57 0 0"/>
      <geometry>
        <mesh filename="package://turtlebot3_description/meshes/wheels/left_tire.stl" scale="0.001 0.001 0.001"/>
      </geometry>
      <material name="dark"/>
    </visual>

    <collision>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <cylinder length="0.018" radius="0.033"/>
      </geometry>
    </collision>

    <inertial>
      <origin xyz="0 0 0" />
      <mass value="2.8498940e-02" />
      <inertia ixx="1.1175580e-05" ixy="-4.2369783e-11" ixz="-5.9381719e-09"
               iyy="1.1192413e-05" iyz="-1.4400107e-11"
               izz="2.0712558e-05" />
      </inertial>
  </link>

  <joint name="wheel_right_joint" type="continuous">
    <parent link="base_link"/>
    <child link="wheel_right_link"/>
    <origin xyz="0.0 -0.144 0.023" rpy="-1.57 0 0"/>
    <axis xyz="0 0 1"/>
  </joint>

  <link name="wheel_right_link">
    <visual>
      <origin xyz="0 0 0" rpy="1.57 0 0"/>
      <geometry>
        <mesh filename="package://turtlebot3_description/meshes/wheels/right_tire.stl" scale="0.001 0.001 0.001"/>
      </geometry>
      <material name="dark"/>
    </visual>

    <collision>
      <origin xyz="0 0 ...