The value of TCPPING->initial_hosts is empty in the embedded tcp.xml

In Jgroups 4.2.6 the embedded tcp.xml file contains among other things:

    <TCPPING async_discovery="true"
             initial_hosts="${jgroups.tcpping.initial_hosts:localhost[7800],localhost[7801]}"
             port_range="2"/>

which became in 4.2.7:

    <TCPPING async_discovery="true"
             initial_hosts=""
             port_range="2"/>

I can see the source file on github still have the expected value, so it feels like a build behavior change that would now interpret some variables (some remain) located in the tcp.xml file (and probably others, but I only checked this file) as an empty value.

My use case is to use the standard tcp.xml file and customize it through system properties, but it's not possible anymore to set the initial_hosts.