TF error in ar_track_alvar

edit

I am running ar_track_alvar to find a marker bundle (using a Kinect 2). The following error occurs:

[ros.ar_track_alvar]: ERROR InferCorners: "ar_marker_0" passed to lookupTransform argument source_frame does not exist.

With rostopic echo /ar_pose_marker I get the list of found marker bundles. There is only one marker bundle present in the real world. However, always two marker bundles are found. The found marker bundles are identical (same marker ID, and exactly the same pose), except for the frame_id. One marker bundle frame id is kinect2_rgb_optical_frame and the other found marker bundle frame id is empty.

I would assume that only one marker bundle should be published (the one with the frame id filled in) and that the error comes from the marker bundle without a frame ID.

I am running ar_track_alvar/findMarkerBundles with this command:

rosrun ar_track_alvar findMarkerBules 5.5 0.08 0.2 /kinect2/hd/points /kinect2/hd/camera_info kinect2_rgb_optical_frame 10 cube.xml

Does anyone know why this error occurs? And how to solve it?

Why are two (identical) marker bundles published, and one with an empty frame id?

This issue does not occur when I use the option to find individual markers instead of marker bundles. The issue is also present when I use another camera (Asus Xtion).