why tf_monitor shows unknown_publisher

edit

C:\fakepath\frames.PNG

I have uploaded the frames -screen capture (as PDF upload is not allowed).

I am getting the same issue as mentioned in the original question. The "unknown_publisher" is evident in the tf_monitor, but the view_frames seems to capture the frames nicely in the pdf output (which is attached as image)

rosrun tf tf_monitor:

RESULTS: for all Frames

Frames:
Frame: base_link published by unknown_publisher Average Delay: 0.00316206 Max Delay: 0.007
Frame: chassis_link published by unknown_publisher Average Delay: -0.499984 Max Delay: 0
Frame: fenders_link published by unknown_publisher Average Delay: -0.499984 Max Delay: 0
Frame: front_laser published by unknown_publisher Average Delay: -0.499984 Max Delay: 0
Frame: front_laser_mount published by unknown_publisher Average Delay: -0.499984 Max Delay: 0
Frame: front_left_wheel_link published by unknown_publisher Average Delay: 0.000171669 Max Delay: 0.004
Frame: front_mount published by unknown_publisher Average Delay: -0.499984 Max Delay: 0
Frame: front_right_wheel_link published by unknown_publisher Average Delay: 0.000172869 Max Delay: 0.004
Frame: imu_link published by unknown_publisher Average Delay: -0.499984 Max Delay: 0
Frame: mid_mount published by unknown_publisher Average Delay: -0.499984 Max Delay: 0
Frame: navsat_link published by unknown_publisher Average Delay: -0.499983 Max Delay: 0
Frame: rear_left_wheel_link published by unknown_publisher Average Delay: 0.000172869 Max Delay: 0.004
Frame: rear_mount published by unknown_publisher Average Delay: -0.499983 Max Delay: 0
Frame: rear_right_wheel_link published by unknown_publisher Average Delay: 0.00017407 Max Delay: 0.004

All Broadcasters:
Node: unknown_publisher 150.128 Hz, Average Delay: -0.165474 Max Delay: 0.006