diff --git a/lib/chibi/regexp.scm b/lib/chibi/regexp.scm
index 1440a86a..40ef0070 100644
--- a/lib/chibi/regexp.scm
+++ b/lib/chibi/regexp.scm
@@ -267,15 +267,16 @@
                    (regexp-match-ref m2 (+ i 1))))
         (lp (+ i 2)))
        ((and (string-cursor? (regexp-match-ref m2 i))
-             (string-cursor? (regexp-match-ref m2 (+ i 1)))
              (or (not (string-cursor? (regexp-match-ref m1 i)))
-                 (not (string-cursor? (regexp-match-ref m1 (+ i 1))))
                  (string-cursor<? (regexp-match-ref m2 i)
                                   (regexp-match-ref m1 i))
-                 (and (string-cursor=? (regexp-match-ref m2 i)
-                                       (regexp-match-ref m1 i))
-                      (string-cursor>? (regexp-match-ref m2 (+ i 1))
-                                       (regexp-match-ref m1 (+ i 1))))))
+                 (and
+                  (string-cursor=? (regexp-match-ref m2 i)
+                                   (regexp-match-ref m1 i))
+                  (or (not (string-cursor? (regexp-match-ref m2 (+ i 1))))
+                      (and (string-cursor? (regexp-match-ref m1 (+ i 1)))
+                           (string-cursor>? (regexp-match-ref m2 (+ i 1))
+                                            (regexp-match-ref m1 (+ i 1))))))))
         #f)
        (else
         #t)))))
diff --git a/tests/regexp-tests.scm b/tests/regexp-tests.scm
index 72a034b0..ef21d0e3 100644
--- a/tests/regexp-tests.scm
+++ b/tests/regexp-tests.scm
@@ -72,6 +72,11 @@
      (regexp-matches '(or (-> foo "ab") (-> foo "cd")) "cd")
      'foo))
 
+;; non-deterministic case from issue #229
+(let* ((elapsed '(: (** 1 2 num) ":" num num (? ":" num num)))
+       (span (rx ,elapsed "-" ,elapsed)))
+  (test-re-search '("1:45:02-2:06:13") span " 1:45:02-2:06:13 "))
+
 (test-re '("ababc" "abab")
          '(: bos ($ (* "ab")) "c")
          "ababc")