diff --git a/crates/proof/src/es/grammar.rs b/crates/proof/src/es/grammar.rs
index 42eede50..687ecac3 100644
--- a/crates/proof/src/es/grammar.rs
+++ b/crates/proof/src/es/grammar.rs
@@ -75,11 +75,21 @@ fn spaces(text: &str, lang: ProofLang, v: &mut Vec<Issue>) {
             v.push(issue(i, i + 1 + p.len_utf8(), "Espacio antes de un signo de puntuación".into(), vec![p.to_string()], lang));
         }
     }
-    for (i, _) in text.match_indices("  ") {
-        if i > 0 && text.get(..i).is_some_and(|t| t.ends_with(' ')) {
+    // Each run of two or more spaces once, over the whole run.
+    let bytes = text.as_bytes();
+    let mut i = 0;
+    while i < bytes.len() {
+        if bytes.get(i) != Some(&b' ') {
+            i += 1;
             continue;
         }
-        v.push(issue(i, i + 2, "Espacio doble".into(), vec![" ".into()], lang));
+        let start = i;
+        while bytes.get(i) == Some(&b' ') {
+            i += 1;
+        }
+        if i - start >= 2 {
+            v.push(issue(start, i, "Espacio doble".into(), vec![" ".into()], lang));
+        }
     }
 }
 
@@ -194,6 +204,16 @@ mod tests {
             .collect()
     }
 
+    /// craft-libs#496 review: a run of spaces is one issue over the whole run.
+    #[test]
+    fn a_run_of_spaces_is_reported_whole() {
+        for (text, run) in [("casa  roja", "  "), ("casa   roja", "   "), ("casa    roja", "    "), ("casa     roja", "     ")] {
+            let m: Vec<_> = messages(text).into_iter().filter(|(_, msg)| msg == "Espacio doble").collect();
+            assert_eq!(m, [(run.to_string(), "Espacio doble".to_string())], "{text}");
+        }
+        assert!(messages("casa roja").is_empty());
+    }
+
     #[test]
     fn repeated_words_and_spaces_have_spanish_messages() {
         let text = "Es es la casa ,  dijo.";