[Help-bash] What causes while-read loop to terminate at round 1 when ssh is used inside the loop?

[Peng Yu]

The following code will only run for the first localhost but not the
second. Does anybody know what is wrong with it?

#!/usr/bin/env bash

while read -r -d $'\n' h
do
  echo "$h"
  ssh "$h" "last | grep '$USER' | head"
done < <(printf "%s\n" localhost localhost)

-- 
Regards,
Peng