diff --git a/test/validate_response.ml b/test/validate_response.ml
index e9ee6bd6..6b65e01e 100644
--- a/test/validate_response.ml
+++ b/test/validate_response.ml
@@ -126,7 +126,14 @@ let keys content =
                     }))
   in
   let* () =
-    if !last_issue_date = v.list_issue_date then Ok ()
+    let last_issue_date =
+      v.denominations
+      |> List.concat_map (fun (DenomGroup.Rsa rsa_denom_group) ->
+          rsa_denom_group.denoms)
+      |> List.map (fun rsa_denom -> rsa_denom.RsaDenom.stamp_start)
+      |> List.fold_left Timestamp.max Timestamp.zero
+    in
+    if last_issue_date = v.list_issue_date then Ok ()
     else Fmt.error "list_issue_date is wrong"
   in