Zebra label printer (printserver) being duplicated in JetAdvice Manager is related to the use of local Mac address in the Zebra label printer (printserver).

As the Zebra label printer (printserver) does not shown a serial number,  JetAdvice Manager sees the printer as a new printer every time the Mac address is changed as the Mac address is the unique identifier in JetAdvice manager.

The solution is to use a static Mac address in the Zebra label printer (printserver) to avoid printers being duplicated in JetAdvice Manager.