diff --git a/yarn-project/pxe/src/database/kv_pxe_database.ts b/yarn-project/pxe/src/database/kv_pxe_database.ts
index cfd620944fd..2b1956efa98 100644
--- a/yarn-project/pxe/src/database/kv_pxe_database.ts
+++ b/yarn-project/pxe/src/database/kv_pxe_database.ts
@@ -76,7 +76,8 @@ export class KVPxeDatabase implements PxeDatabase {
 
   getContractArtifact(id: Fr): Promise<ContractArtifact | undefined> {
     const contract = this.#contractArtifacts.get(id.toString());
-    return Promise.resolve(contract && contractArtifactFromBuffer(contract));
+    // TODO(@spalladino): AztecMap lies and returns Uint8Arrays instead of Buffers, hence the extra Buffer.from.
+    return Promise.resolve(contract && contractArtifactFromBuffer(Buffer.from(contract)));
   }
 
   async addContractInstance(contract: ContractInstanceWithAddress): Promise<void> {
diff --git a/yarn-project/types/src/abi/contract_artifact.ts b/yarn-project/types/src/abi/contract_artifact.ts
index cdbf3f90107..221fb7c80c4 100644
--- a/yarn-project/types/src/abi/contract_artifact.ts
+++ b/yarn-project/types/src/abi/contract_artifact.ts
@@ -17,7 +17,7 @@ import { mockVerificationKey } from './mocked_keys.js';
  */
 export function contractArtifactToBuffer(artifact: ContractArtifact): Buffer {
   // TODO(@spalladino): More efficient serialization
-  return Buffer.from(JSON.stringify(artifact));
+  return Buffer.from(JSON.stringify(artifact), 'utf8');
 }
 
 /**
@@ -27,7 +27,7 @@ export function contractArtifactToBuffer(artifact: ContractArtifact): Buffer {
  */
 export function contractArtifactFromBuffer(buffer: Buffer): ContractArtifact {
   // TODO(@spalladino): More efficient serialization
-  return JSON.parse(buffer.toString()) as ContractArtifact;
+  return JSON.parse(buffer.toString('utf8')) as ContractArtifact;
 }
 
 /**