diff --git a/pageserver/src/tenant/layer_map.rs b/pageserver/src/tenant/layer_map.rs
index 0787c80708..7b76199190 100644
--- a/pageserver/src/tenant/layer_map.rs
+++ b/pageserver/src/tenant/layer_map.rs
@@ -51,7 +51,7 @@ use crate::keyspace::KeyPartitioning;
 use crate::repository::Key;
 use crate::tenant::storage_layer::InMemoryLayer;
 use crate::tenant::storage_layer::Layer;
-use anyhow::Result;
+use anyhow::{bail, Result};
 use std::collections::VecDeque;
 use std::ops::Range;
 use std::sync::Arc;
@@ -276,16 +276,22 @@ where
     ///
     pub(self) fn insert_historic_noflush(&mut self, layer: Arc<L>) -> anyhow::Result<()> {
         let key = historic_layer_coverage::LayerKey::from(&*layer);
-        if self.historic.contains(&key) {
-            error!(
-                "Attempt to insert duplicate layer {} in layer map",
-                layer.short_id()
-            );
-        } else {
-            self.historic.insert(key, Arc::clone(&layer));
+        match self.historic.replace(&key, Arc::clone(&layer), |existing| {
+            !Self::compare_arced_layers(existing, &layer)
+        }) {
+            Replacement::Replaced { .. } => {
+                if Self::is_l0(&layer) {
+                    bail!("Duplicate L0 layer {}", layer.short_id());
+                }
+                warn!("Replace duplicate layer {} in layer map", layer.short_id());
+            }
+            Replacement::Unexpected(_) => bail!("Replace layer with itslef is prohibited"),
+            Replacement::NotFound | Replacement::RemovalBuffered => {
+                self.historic.insert(key, Arc::clone(&layer));
 
-            if Self::is_l0(&layer) {
-                self.l0_delta_layers.push(layer);
+                if Self::is_l0(&layer) {
+                    self.l0_delta_layers.push(layer);
+                }
             }
         }
         Ok(())
diff --git a/pageserver/src/tenant/layer_map/historic_layer_coverage.rs b/pageserver/src/tenant/layer_map/historic_layer_coverage.rs
index 1fdcd5e5a4..b63c361314 100644
--- a/pageserver/src/tenant/layer_map/historic_layer_coverage.rs
+++ b/pageserver/src/tenant/layer_map/historic_layer_coverage.rs
@@ -417,14 +417,6 @@ impl<Value: Clone> BufferedHistoricLayerCoverage<Value> {
         }
     }
 
-    pub fn contains(&self, layer_key: &LayerKey) -> bool {
-        match self.buffer.get(layer_key) {
-            Some(None) => false,                         // layer remove was buffered
-            Some(_) => true,                             // layer insert was buffered
-            None => self.layers.contains_key(layer_key), // no buffered ops for this layer
-        }
-    }
-
     pub fn insert(&mut self, layer_key: LayerKey, value: Value) {
         self.buffer.insert(layer_key, Some(value));
     }
diff --git a/test_runner/regress/test_duplicate_layers.py b/test_runner/regress/test_duplicate_layers.py
index 4ff4e1e288..77d79cfcc0 100644
--- a/test_runner/regress/test_duplicate_layers.py
+++ b/test_runner/regress/test_duplicate_layers.py
@@ -16,7 +16,7 @@ def test_duplicate_layers(neon_env_builder: NeonEnvBuilder, pg_bin: PgBin):
     # These warnings are expected, when the pageserver is restarted abruptly
     env.pageserver.allowed_errors.append(".*found future image layer.*")
     env.pageserver.allowed_errors.append(".*found future delta layer.*")
-    env.pageserver.allowed_errors.append(".*Attempt to insert duplicate layer.*")
+    env.pageserver.allowed_errors.append(".*duplicate layer.*")
 
     pageserver_http = env.pageserver.http_client()