NetworkManager - if-down.d script does not execute

I am trying to use /etc/network/if-up.d/ and /etc/network/if-down.d to send an SMS from my computer to my phone via Gmail whenever my computer enters or exits a wireless network. The main script is written in Perl, and the scripts in said folders are essentially wrappers around it. Here is the Perl script, ~user/bin/laptopSMS.pl:

#!/usr/bin/perl

use strict;
use warnings;

use Email::Send;
use Email::Send::Gmail;
use Email::Simple::Creator;

my $addy = q{[email protected]};
my $pass  = q{myPass};
my $sms   = q{[email protected]};

my $email = Email::Simple->create(
   header => [
          From    => $addy,
              To      => $sms,
          Subject => "$ARGV[0]",
  ],
  body => "$ARGV[1] / $ARGV[2]",
);

my $sender = Email::Send->new(
    {     mailer      => 'Gmail',
          mailer_args => [
              username => $addy,
              password => $pass,
          ]
    }
 );
eval { $sender->send($email) };
die "Error sending email: $@" if $@;

The following script is /etc/network/if-up.d/99postconnect_laptopSMS:

#!/bin/bash

set -e

if [ "$IFACE" == "wlan0" ]; then
    ipaddr=`ip addr | grep inet[^6] | grep -v 127.0.0.1 | awk {'print $2'} | sed 's!/[0-9]*!!g'`
    ssid=`iwgetid -r`
    ~user/bin/laptopSMS.pl "connected" "$ssid" "$ipaddr"
fi

This works fine, and I get a text message whenever my phone enters a network; the corresponding if-down.d script to send a "disconnect" signal, however, does not:

#!/bin/bash

set -e

if [ "$IFACE" == "wlan0" ]; then
    ~user/bin/laptopSMS.pl "disconnect" "disconnect" "disconnect"
fi

This is not executing; I tried to put the following snippet into the script to see if anything is actually running:

ifdowntest=/home/user/ifdown_test.txt
date >> $ifdowntest
whoami >> $ifdowntest
ifconfig >> $ifdowntest
sleep 5

Leaving this in the script by itself executes just fine, but appending it to the wrapper to the Perl script does not. (No file is generated.)

The output of ifconfig >> $ifdowntest shows that wlan0 does not have an IP - it's been taken down. Can I get this script to execute pre-down (I thought that's what the if-down.d folder did) or somehow edit something to make this work? Note that it takes about 3 seconds for the Perl script to fire when running it manually.

FWIW: I'm taking down the network manually by clicking the NetworkManager applet and clicking "Disconnect". I could potentially just kill my router to test that too, but I don't know if there's a difference between manually disconnecting and the AP no longer existing.