diff --git a/etherlink/CHANGES_NODE.md b/etherlink/CHANGES_NODE.md
index c5b6e4354d2dfd6e5b2c648f7d3ac81909f82dba..501fa884a6cb399066a1d8cc4046c5863bd92419 100644
--- a/etherlink/CHANGES_NODE.md
+++ b/etherlink/CHANGES_NODE.md
@@ -7,6 +7,9 @@
 ### Bug fixes
 
 - Default rollup node port is 8932, not 8937. (!15701)
+- Reintroduces a safety guard removed in previous version, checks the L1 block
+  level provided by the rollup node, always ignore it if it was already
+  processed. (!15724)
 
 ### Internals
 
diff --git a/etherlink/bin_node/lib_dev/evm_context.ml b/etherlink/bin_node/lib_dev/evm_context.ml
index 0cf4e297f51098a0eab3057a16bebb84d1e16c31..e9ec6df836b1f0ebd865c683dfbcde4e7f71f92b 100644
--- a/etherlink/bin_node/lib_dev/evm_context.ml
+++ b/etherlink/bin_node/lib_dev/evm_context.ml
@@ -611,6 +611,34 @@ module State = struct
     let (Qty next_blueprint_number) = ctxt.session.next_blueprint_number in
     Ethereum_types.Qty (Z.pred next_blueprint_number)
 
+  let needs_process_l1_block ctxt rollup_block_level =
+    let open Lwt_result_syntax in
+    let* last_known_l1_block =
+      let* level =
+        Evm_store.use ctxt.store @@ fun conn ->
+        Evm_store.L1_l2_levels_relationships.find conn
+      in
+      match level with
+      | Some {l1_level; _} -> return_some l1_level
+      | None -> return_none
+    in
+    match last_known_l1_block with
+    | None -> return_true
+    | Some last_known_l1_block ->
+        let level_expected = Int32.succ last_known_l1_block in
+        if Int32.equal rollup_block_level level_expected then return_true
+        else if Compare.Int32.(rollup_block_level < level_expected) then
+          let*! () =
+            Evm_context_events.unexpected_l1_block
+              ~expected_level:level_expected
+              ~provided_level:rollup_block_level
+          in
+          return false
+        else
+          tzfail
+            (Node_error.Out_of_sync
+               {level_received = rollup_block_level; level_expected})
+
   let apply_evm_events ?finalized_level (ctxt : t) events =
     let open Lwt_result_syntax in
     let* needs_process =
@@ -619,32 +647,7 @@ module State = struct
           (* We are not taking events from a rollup block, we don't need to check
              if it's the last known l1 block successor. *)
           return_true
-      | Some rollup_block_level -> (
-          let* last_known_l1_block =
-            let* level =
-              Evm_store.use ctxt.store @@ fun conn ->
-              Evm_store.L1_l2_levels_relationships.find conn
-            in
-            match level with
-            | Some {l1_level; _} -> return_some l1_level
-            | None -> return_none
-          in
-          match last_known_l1_block with
-          | None -> return_true
-          | Some last_known_l1_block ->
-              let level_expected = Int32.succ last_known_l1_block in
-              if Int32.equal rollup_block_level level_expected then return_true
-              else if Compare.Int32.(rollup_block_level < level_expected) then
-                let*! () =
-                  Evm_context_events.unexpected_l1_block
-                    ~expected_level:level_expected
-                    ~provided_level:rollup_block_level
-                in
-                return false
-              else
-                tzfail
-                  (Node_error.Out_of_sync
-                     {level_received = rollup_block_level; level_expected}))
+      | Some finalized_level -> needs_process_l1_block ctxt finalized_level
     in
     if needs_process then (
       let* context, evm_state, on_success =
@@ -1471,14 +1474,17 @@ module Handlers = struct
     | New_last_known_L1_level l1_level ->
         protect @@ fun () ->
         let ctxt = Worker.state self in
-        Evm_store.use ctxt.store @@ fun conn ->
-        let l2_level = State.current_blueprint_number ctxt in
-        let*! () = Evm_context_events.processed_l1_level l1_level in
-        Evm_store.L1_l2_levels_relationships.store
-          conn
-          ~latest_l2_level:l2_level
-          ~l1_level
-          ~finalized_l2_level:ctxt.session.finalized_number
+        let* needs_process = State.needs_process_l1_block ctxt l1_level in
+        if needs_process then
+          let*! () = Evm_context_events.processed_l1_level l1_level in
+          Evm_store.use ctxt.store @@ fun conn ->
+          let l2_level = State.current_blueprint_number ctxt in
+          Evm_store.L1_l2_levels_relationships.store
+            conn
+            ~latest_l2_level:l2_level
+            ~l1_level
+            ~finalized_l2_level:ctxt.session.finalized_number
+        else return_unit
     | Delayed_inbox_hashes ->
         protect @@ fun () ->
         let ctxt = Worker.state self in