No output from AgentExecuteActionWithOutput

[johnnyva]

Server environments:

• Instance 1 = v3.8.166 on Ubuntu Bionic (AgentExecuteActionWithOutput doesn't work)
• Instance 2 = v3.4.313 on Ubuntu Xenial (AgentExecuteActionWithOutput works)

When executing nxsl script against Instance 1 environment, and running the following command, I get no output.  This has been a thing for a while (going off my poor memory, I'm sure it used to work, but I don't think it has since 3.6ish? but I could be wrong and maybe it's never worked...)

println(AgentExecuteActionWithOutput($node, "echo test"));

This should print out "test".
When running this against our Instance 2 environment, I get the expected result (i.e. it prints out "test").

This could be a agent config or setting somewhere but struggling to find it.

Both servers have almost the same nxagentd.conf execpt for the MasterServers settings.

Both have the following nxagentd.conf

# Log File
LogFile=/var/log/nxagentd

# IP white list, can contain multiple records separated by comma.
# CIDR notation supported for subnets.
MasterServers=<redacted>,127.0.0.0/8

SubAgent = filemgr.nsm

[filemgr]
RootFolder = /

And when running the nxagentd -C on the working server instance, it does not contain any extra agent settings that might have been applied by agent policies.

Any ideas?