XDCR Target nozzle value set to 64 after upgrade from 3.X to 4.X and persists even after upgrade to 5.X

Issue:

On an environment upgraded from Couchbase 3.X series to 4.X series, when a XDCR replication stream is created, the default value of the "XDCR Target Nozzles per Node" parameter is set to "64" instead of "2".  However, clean installation of 4.6.3 shows the default value of this parameter as "2". The value of "64" for this parameter, also propagates over to the 5.X environments, when the 4.X environments are upgraded.

Note: This issue does not occur, when the upgrade is perform from a clean install of 4.X to 5.X.

Description:

• When a clean install of 4.6.3 version is performed,  the default value of the  "XDCR Target Nozzles per Node" parameter is  "2" as shown below:

• In 3.X, the parameter "XDCR Target Nozzles per Node" does not exist in the XDCR settings:

• After upgrading to 4.X series from 3.X, the default value of the parameter "XDCR Target Nozzles per Node" is 64:

• After upgrading to 5.X series from 4.X, the default value of the parameter "XDCR Target Nozzles per Node" is still 64:

Expected Behavior:

The default value of the parameter "XDCR Target Nozzles per Node" should be "2" instead of "64". "64" is a high value for this parameter and can affect the performance of both the source and target clusters.