Live Link VRPN cannot recognize multiple tracking targets

I’m trying to pass the tracking information of 3 targets obtained by DTrack of ar-tracking to Live Link VRPN via VRPN server, but it doesn’t work.

When I check the information in the VRPN utility, three objects and button input and joystick input are recognized.

In VRPN in nDisplay of UE4.26, the mapping of 3 objects was done normally. (Assigned as Head, Hand, Wand)

Only one target is displayed in the tracker information in the Live Link window of UE4.27.
When I check the frame information, the position information and angle information have changed significantly even though I haven’t moved the target.

Is it possible that Live Link VRPN cannot divide the measurement information of three targets and recognizes them as one target?

Does anyone use Live Link VRPN to accurately recognize multiple targets sent by the VRPN server?

Thank you,