diff --git a/tezt/tests/dal.ml b/tezt/tests/dal.ml
index 718eb533f6543a113b8095c2a23ae7f2f9e4e828..4c9976d199d224920fe1ff15ff26d80fffaddf06 100644
--- a/tezt/tests/dal.ml
+++ b/tezt/tests/dal.ml
@@ -249,7 +249,7 @@ let wait_for_shards_promises ~dal_node ~shards ~published_level ~slot_index =
         in
         let () = incr count in
         let () =
-          Log.info
+          Log.debug
             "Dal node %s has received %d/%d shards"
             (Dal_node.name dal_node)
             !count
@@ -6028,7 +6028,7 @@ module Amplification = struct
         wait_for_shards_promises ~dal_node ~shards ~published_level ~slot_index
       in
       let () =
-        Log.info "Dal node %s has received its shards" (Dal_node.name dal_node)
+        Log.debug "Dal node %s has received its shards" (Dal_node.name dal_node)
       in
       unit
     in
@@ -6073,7 +6073,7 @@ module Amplification = struct
       unit
     in
 
-    (* Wait until everyone has reveived the needed shards (first the
+    (* Wait until everyone has received the needed shards (first the
        non-banned attesters, then the observer, and finally the banned
        attesters). *)
     let wait_slot ~published_level ~slot_index =
@@ -10768,6 +10768,13 @@ let register ~protocols =
     ~tags:["amplification"; "simple"]
     ~bootstrap_profile:true
     ~l1_history_mode:Default_with_refutation
+      (* In this test, receiving all shards should happen before amplification
+         starts. With [minimal_block_delay = 1], it may start 1 second after the
+         first shard is received, which results in flakiness. With
+         [minimal_block_delay = 3], it may start only after 4s (see !18139),
+         which should be enough time for the observer to receive all the
+         shards. *)
+    ~minimal_block_delay:"3"
     "observer triggers amplification (without lost shards)"
     Amplification.test_amplification_without_lost_shards
     protocols ;