ZMIRROR - Illegal Value

I am trying to work on a ZMIRROR that will execute a shell script to failover our VIP at the hardware level when NotifyBecomePrimary occurs.

ZMIRROR ; Custom logic for specific mirroring events
 q
 ;
NotifyBecomePrimary() PUBLIC {
 #;This procedure is called as a notification when this system becomes Primary.
 #;It does not return any value.
 #; invoke the command to select this host for running the crontab
 try {
	Set cmd = "/usr/local/sbin/failover-intengtest-vip_SR"
	d $ZF(-100,"/SHELL /LOGCMD /STDOUT=/archive/logs/failover-intengtest-vip.log""",cmd)
    }
 catch e {
     d ##class(%SYS.System).WriteToConsoleLog("NotifyBecomePrimary^ZMIRROR error: "_e.AsSystemError(),,1)
     }
 q
}

I verified the $ZF syntax by creating a smaller script and executing it via terminal. However when ZMIRROR is executed when I am attempting to failover I am getting the following in messages.log

01/13/24-14:47:47:812 (4104771) 1 [Utility.Event] NotifyBecomePrimary^ZMIRROR error: <ILLEGAL VALUE>NotifyBecomePrimary+3^ZMIRROR

Can anyone see what the Illegal Value might be?