diff --git a/crates/doc/src/lib.rs b/crates/doc/src/lib.rs
index 0181ffd21..1349aac1d 100644
--- a/crates/doc/src/lib.rs
+++ b/crates/doc/src/lib.rs
@@ -1098,6 +1098,9 @@ impl Document {
         // lookups: a wide parent or a long page list doesn't make validation quadratic.
         let edges: std::collections::BTreeSet<(NodeId, NodeId)> = self.nodes.iter().flat_map(|(p, n)| n.children.iter().map(|c| (*p, *c))).collect();
         let page_ids: std::collections::BTreeSet<NodeId> = self.pages.iter().copied().collect();
+        if page_ids.len() != self.pages.len() {
+            note(&mut issues, || "a page is listed twice".to_string());
+        }
         for (id, n) in self.nodes.iter() {
             if n.id != *id {
                 note(&mut issues, || format!("node key {id} has id {}", n.id));
@@ -1191,9 +1194,10 @@ impl Document {
         if store != self.libraries.store {
             Arc::make_mut(&mut self.libraries).store = store;
         }
-        self.pages.retain(|p| self.nodes.get(p).is_some_and(|n| n.is_page()) && Some(*p) != store);
+        // A page listed twice would be imported, exported and walked once per listing.
+        let mut listed = std::collections::BTreeSet::new();
+        self.pages.retain(|p| self.nodes.get(p).is_some_and(|n| n.is_page()) && Some(*p) != store && listed.insert(*p));
         // Unlisted pages join the list; a set keeps many pages from making this quadratic (#1078).
-        let mut listed: std::collections::BTreeSet<NodeId> = self.pages.iter().copied().collect();
         for (k, n) in self.nodes.iter() {
             if n.is_page() && Some(*k) != store && listed.insert(*k) {
                 self.pages.push(*k);
diff --git a/crates/doc/src/tests.rs b/crates/doc/src/tests.rs
index a5c8e8e7a..6ac6f455b 100644
--- a/crates/doc/src/tests.rs
+++ b/crates/doc/src/tests.rs
@@ -348,6 +348,20 @@ fn repair_drops_cycles_and_repeated_children() {
     assert_eq!(bad.subtree(p), vec![p, r]);
 }
 
+#[test]
+fn repair_lists_a_page_once_however_often_the_file_lists_it() {
+    let mut d = Document::new("x");
+    let p = page(&d);
+    let q = d.add_page("Two");
+    let mut v = serde_json::to_value(&d).unwrap();
+    v["pages"] = serde_json::json!([p, q, p, q, p]);
+    let mut bad: Document = serde_json::from_value(v).unwrap();
+    assert!(bad.validate().iter().any(|i| i.contains("listed twice")), "{:?}", bad.validate());
+    bad.repair();
+    assert!(bad.validate().is_empty(), "{:?}", bad.validate());
+    assert_eq!(bad.pages, vec![p, q]);
+}
+
 #[test]
 fn validate_caps_the_issue_list() {
     let mut d = Document::new("x");