sub ReportThreshholdExceeded
{
      my $output_array = shift;
        my $text = join "\t", @{$output_array};
        
        LogMsg("Running ReportThreshholdExceeded");
                
    my $msg = <<END_OF_BODY;

The number of SKUs that have been flagged as DeleteMe is greater than 
+the threshold of $threshold and thus Manager approval is required.

Here is the list of SKUs and their counts:

PLANNERCODE\tDEALER\tCOUNT
=================================
$text




The MDI Server

END_OF_BODY

    my $address = "ssmith\@xyz.com";

    open(MAILER, "| mailx -s \"Manager Approval Required for DeleteMe 
+flagged SKUs on $instance\" $address")
               or warn("Couldn't start mailx: $!\n");

    print MAILER $msg;       # send the mail

    close(MAILER);
    
    LogMsg("Email sent");
}
[download]

How are you calling the subroutine? If you do

ReportThreshholdExceeded $thing1, $thing2, $thing3;
[download]

then $output_array = $thing1. Maybe you actually meant

my @output_array = @_;
my $text = join "\t", @output_array;
...
[download]

This puts all parameters in $output_array.