Hmm...maybe your $t->output_record_separator() is set to something weird? (or, in any event, something inconsistent with what the machine at the other end is expecting)

I'm having trouble coming up with other explanations. If it doesn't time out, and it doesn't fail to match, it ought to be sending the \n across the wire when prompted unless the ORS is fouled up. I'm not sure why you broke up the match into two pieces here, but I don't think that should matter.