diff --git a/Cargo.lock b/Cargo.lock
index 9be4a2b1e4..0548c11918 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5602,6 +5602,7 @@ dependencies = [
  "pretty_assertions",
  "quote",
  "scale-info",
+ "scale-typegen",
  "scale-typegen-description",
  "scale-value",
  "serde",
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index 6b91fea425..47e8ddccee 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -27,6 +27,7 @@ chain-spec-pruning = ["smoldot"]
 
 [dependencies]
 subxt-codegen = { workspace = true }
+scale-typegen = { workspace = true }
 subxt-utils-fetchmetadata = { workspace = true, features = ["url"] }
 subxt-utils-stripmetadata = { workspace = true }
 subxt-metadata = { workspace = true }
diff --git a/cli/src/commands/codegen.rs b/cli/src/commands/codegen.rs
index e7b8f070c5..10744aed76 100644
--- a/cli/src/commands/codegen.rs
+++ b/cli/src/commands/codegen.rs
@@ -210,8 +210,18 @@ fn codegen(
         codegen.no_docs()
     }
 
-    let metadata = subxt_metadata::Metadata::decode(&mut &*metadata_bytes)
-        .map_err(|e| eyre!("Cannot decode the provided metadata: {e}"))?;
+    let metadata = {
+        let mut metadata = subxt_metadata::Metadata::decode(&mut &*metadata_bytes)
+            .map_err(|e| eyre!("Cannot decode the provided metadata: {e}"))?;
+
+        // Run this first to ensure type paths are unique (which may result in 1,2,3 suffixes being added
+        // to type paths), so that when we validate derives/substitutions below, they are allowed for such
+        // types. See <https://github.com/paritytech/subxt/issues/2011>.
+        scale_typegen::utils::ensure_unique_type_paths(metadata.types_mut())
+            .expect("ensure_unique_type_paths should not fail; please report an issue.");
+
+        metadata
+    };
 
     // Configure derives:
     let global_derives = raw_derives
diff --git a/macro/src/lib.rs b/macro/src/lib.rs
index 355372f672..c3e00da1b9 100644
--- a/macro/src/lib.rs
+++ b/macro/src/lib.rs
@@ -102,7 +102,17 @@ fn subxt_inner(args: TokenStream, item_mod: syn::ItemMod) -> Result<TokenStream,
         .map_err(|e| TokenStream::from(e.write_errors()))?;
 
     // Fetch metadata first, because we need it to validate some of the chosen codegen options.
-    let metadata = fetch_metadata(&args)?;
+    let metadata = {
+        let mut metadata = fetch_metadata(&args)?;
+
+        // Run this first to ensure type paths are unique (which may result in 1,2,3 suffixes being added
+        // to type paths), so that when we validate derives/substitutions below, they are allowed for such
+        // types. See <https://github.com/paritytech/subxt/issues/2011>.
+        scale_typegen::utils::ensure_unique_type_paths(metadata.types_mut())
+            .expect("ensure_unique_type_paths should not fail; please report an issue.");
+
+        metadata
+    };
 
     let mut codegen = CodegenBuilder::new();
 
@@ -135,6 +145,7 @@ fn subxt_inner(args: TokenStream, item_mod: syn::ItemMod) -> Result<TokenStream,
             .into_iter()
             .collect(),
     );
+
     for d in args.derive_for_type {
         validate_type_path(&d.path.path, &metadata);
         codegen.add_derives_for_type(d.path, d.derive.into_iter(), d.recursive);
diff --git a/testing/ui-tests/src/incorrect/substitute_at_wrong_path.stderr b/testing/ui-tests/src/incorrect/substitute_at_wrong_path.stderr
index 333a888b37..a0e35c3950 100644
--- a/testing/ui-tests/src/incorrect/substitute_at_wrong_path.stderr
+++ b/testing/ui-tests/src/incorrect/substitute_at_wrong_path.stderr
@@ -11,9 +11,7 @@ error: Type `Event` does not exist at path `sp_runtime::multiaddress::Event`
        pallet_grandpa::pallet::Event
        pallet_treasury::pallet::Event
        pallet_conviction_voting::pallet::Event
-       pallet_referenda::pallet::Event
        pallet_ranked_collective::pallet::Event
-       pallet_referenda::pallet::Event
        pallet_whitelist::pallet::Event
        polkadot_runtime_common::claims::pallet::Event
        pallet_utility::pallet::Event