diff --git a/packages/beacon-node/src/chain/chain.ts b/packages/beacon-node/src/chain/chain.ts
index 92da02ddab82..20a6ca343565 100644
--- a/packages/beacon-node/src/chain/chain.ts
+++ b/packages/beacon-node/src/chain/chain.ts
@@ -1001,6 +1001,6 @@ export class BeaconChain implements IBeaconChain {
       throw Error(`Pre-state is unavailable given block's parent root ${toHexString(block.parentRoot)}`);
     }
 
-    return computeBlockRewards(block, preState, postState);
+    return computeBlockRewards(block, preState.clone(), postState?.clone());
   }
 }
diff --git a/packages/beacon-node/src/chain/rewards/blockRewards.ts b/packages/beacon-node/src/chain/rewards/blockRewards.ts
index 7fdfe126e122..bd8bf3537582 100644
--- a/packages/beacon-node/src/chain/rewards/blockRewards.ts
+++ b/packages/beacon-node/src/chain/rewards/blockRewards.ts
@@ -94,6 +94,7 @@ function computeSyncAggregateReward(block: altair.BeaconBlock, preState: CachedB
     return 0; // phase0 block does not have syncAggregate
   }
 }
+
 /**
  * Calculate rewards received by block proposer for including proposer slashings.
  * All proposer slashing rewards go to block proposer and none to whistleblower as of Deneb