Any chance this is simply timing out?   Apparently the default timeout for some/most operations including waitfor() is set at new() time and defaults to 10 seconds. (You can change it with timeout()

If we take the Net::Telnet internals as canon,

  ## Wait for login prompt.
  $self->waitfor(-match => '/login[: ]*$/i',
                 -match => '/username[: ]*$/i')
      or do {
          return &$error("read eof waiting for login prompt")
            if $self->eof;
          return &$error("timed-out waiting for login prompt");
      };
[download]

then maybe you should also test for the eof and timeout conditions.

Obligatory nit: I don't think you need to escape the '-' characters if they aren't inside a character class, e.g. /--[!?]--/ )