diff --git a/yarn-project/cli-wallet/src/utils/wallet.ts b/yarn-project/cli-wallet/src/utils/wallet.ts
index 2ace44debe9c..54a37e83a005 100644
--- a/yarn-project/cli-wallet/src/utils/wallet.ts
+++ b/yarn-project/cli-wallet/src/utils/wallet.ts
@@ -275,7 +275,7 @@ export class CLIWallet extends BaseWallet {
     } else {
       const { account, instance } = await this.getFakeAccountDataFor(from);
       overrides = {
-        contracts: { [from.toString()]: { instance } },
+        contracts: { [from.toString()]: { instance, skipSync: true } },
       };
       const executionOptions: DefaultAccountEntrypointOptions = {
         txNonce: Fr.random(),
diff --git a/yarn-project/end-to-end/src/test-wallet/test_wallet.ts b/yarn-project/end-to-end/src/test-wallet/test_wallet.ts
index f559bdda136f..19de078d3e11 100644
--- a/yarn-project/end-to-end/src/test-wallet/test_wallet.ts
+++ b/yarn-project/end-to-end/src/test-wallet/test_wallet.ts
@@ -165,6 +165,7 @@ export class TestWallet extends BaseWallet {
 
       contracts[address.toString()] = {
         instance: { ...contractInstance, currentContractClassId: stubClassId },
+        skipSync: true,
       };
     }
 
diff --git a/yarn-project/pxe/src/pxe.ts b/yarn-project/pxe/src/pxe.ts
index 5c678f8cacfe..28ead692c893 100644
--- a/yarn-project/pxe/src/pxe.ts
+++ b/yarn-project/pxe/src/pxe.ts
@@ -1013,9 +1013,18 @@ export class PXE {
         const contractFunctionSimulator = this.#getSimulatorForTx(overrides);
 
         if (hasOverriddenContracts) {
-          // Overridden contracts don't have a sync function, so calling sync on them would fail.
-          // We exclude them so the sync service skips them entirely.
-          this.contractSyncService.setExcludedFromSync(jobId, overriddenContracts);
+          // Skip sync only for overrides that explicitly opt out (typically mock/stub overrides whose
+          // artifact doesn't model the address's real notes). Real-class overrides (e.g. upgrade
+          // simulations via fastForwardContractUpdate) leave skipSync unset so sync runs as usual
+          // and pre-existing notes get discovered.
+          const skipSyncAddresses = new Set(
+            Object.entries(overrides!.contracts!)
+              .filter(([_addr, override]) => override.skipSync)
+              .map(([addr]) => addr),
+          );
+          if (skipSyncAddresses.size > 0) {
+            this.contractSyncService.setExcludedFromSync(jobId, skipSyncAddresses);
+          }
         }
 
         // Execution of private functions only; no proving, and no kernel logic.
diff --git a/yarn-project/stdlib/src/tx/simulated_tx.ts b/yarn-project/stdlib/src/tx/simulated_tx.ts
index 0ffd03c5674a..b043a180bc00 100644
--- a/yarn-project/stdlib/src/tx/simulated_tx.ts
+++ b/yarn-project/stdlib/src/tx/simulated_tx.ts
@@ -29,8 +29,17 @@ import { Tx } from './tx.js';
  * overriding your own account contract so that valid signatures don't have to be provided while
  * simulating. The override's `currentContractClassId` resolves through PXE's locally registered
  * classes, so pre-register the target artifact via `pxe.registerContractClass(...)`.
+ *
+ * `skipSync` declares that PXE should not run contract sync (note discovery + nullifier sync) for
+ * this address while the override is in effect. Set this for mock/stub overrides whose artifact
+ * doesn't model the address's real notes (e.g. account stubs that mock auth without holding the
+ * real signing key storage). Leave unset (default false) for overrides that target full, on-chain
+ * classes where pre-existing notes still need to be discoverable (e.g. upgrade simulations).
  */
-export type ContractOverrides = Record<string /* AztecAddress as string */, { instance: ContractInstanceWithAddress }>;
+export type ContractOverrides = Record<
+  string /* AztecAddress as string */,
+  { instance: ContractInstanceWithAddress; skipSync?: boolean }
+>;
 
 /*
  * Optional values that can be overridden during simulation. `publicStorage` writes to the public-data
@@ -51,7 +60,12 @@ export class SimulationOverrides {
     return z
       .object({
         publicStorage: optional(z.array(PublicStorageOverrideSchema)),
-        contracts: optional(z.record(z.string(), z.object({ instance: ContractInstanceWithAddressSchema }))),
+        contracts: optional(
+          z.record(
+            z.string(),
+            z.object({ instance: ContractInstanceWithAddressSchema, skipSync: optional(z.boolean()) }),
+          ),
+        ),
       })
       .transform(args => new SimulationOverrides(args));
   }
diff --git a/yarn-project/wallets/src/embedded/embedded_wallet.ts b/yarn-project/wallets/src/embedded/embedded_wallet.ts
index bfddd9907030..495f008fdfc2 100644
--- a/yarn-project/wallets/src/embedded/embedded_wallet.ts
+++ b/yarn-project/wallets/src/embedded/embedded_wallet.ts
@@ -246,6 +246,7 @@ export class EmbeddedWallet extends BaseWallet {
 
       contracts[address.toString()] = {
         instance: { ...contractInstance, currentContractClassId: stubClassId },
+        skipSync: true,
       };
     }