use threads;
use threads::shared;

my $lock:shared;

foreach my $server (@servers) {
  chomp $server;
  push (@threads, threads->create (\&dumpServer, $server));
}
foreach (@threads) { $_->join(); }

sub dumpServer {
  my $server = shift;
  my $net = `ssh -tt $server '/usr/local/bin/tcpdump -c10 -nntttt port 80 2>/dev/null' 2>/dev/null`;  ## This is the line that causes the issue
  lock($lock);
  print "TEST - $server\n";  ## Want to print $net output here, but printing even a simple string gives me the issue
}

##</code><code>##

TEST - Server1
TEST - Server2
    TEST - Server3
    TEST - Server4
         Bash Prompt (now need to reset term)