That is an old example (that was with kinect 360?), if rtabmap is built with OpenGV, I recommend to use default visual odometry settings:
Odom/Strategy=0
OdomF2M/BundleAdjustment=1
Vis/EstimationType = 1
It will be a lot better.
I would not set Vis/MaxDepth=4, keep it to default 0.
cheers,
Mathieu