Trying to parse a file of links with titles, but some unexpected behavior happened.

link-reader.rkt

#lang racket

(require br-parser-tools/lex
         (prefix-in : br-parser-tools/lex-sre))

(module+ test
  (require rackunit))

(define (read-links in)
  (define l
    (lexer
     [(:or blank whitespace) (l in)]
     [(:: "http" (:+ (:~ blank whitespace))) `(url ,lexeme)]
     [(:: (:~ blank whitespace) (:* (:~ #\newline))) `(title ,lexeme)]
     [(eof) (void)]))
  (define (next-token) (l in))
  (let loop ()
    (let ([a (next-token)])
      (if (void? a)
          '()
          (list* a (loop))))))

(module+ test
  (define a
    "
https://abc.com e
our world
on fire
https://www.example.com
")
  (check-equal? (read-links (open-input-string a))
                '((url "https://abc.com")
                  (title "e")
                  (title "our world")
                  (title "on fire")
                  (url "https://www.example.com"))))
                  
#|       
--------------------
. FAILURE
name:       check-equal?
location:   link-reader.rkt:35:2
actual:
  '((title "https://abc.com e")
    (title "our world")
    (title "on fire")
    (url "https://www.example.com"))
expected:
  '((url "https://abc.com")
    (title "e")
    (title "our world")
    (title "on fire")
    (url "https://www.example.com"))
--------------------
|#