diff --git a/lib/optimize/SplitChunksPlugin.js b/lib/optimize/SplitChunksPlugin.js
index 6a19bc58a1e..07102282f54 100644
--- a/lib/optimize/SplitChunksPlugin.js
+++ b/lib/optimize/SplitChunksPlugin.js
@@ -774,9 +774,13 @@ module.exports = class SplitChunksPlugin {
 					const chunkIndexMap = new Map();
 					const ZERO = BigInt("0");
 					const ONE = BigInt("1");
-					let index = ONE;
+					const START = ONE << BigInt("31");
+					let index = START;
 					for (const chunk of chunks) {
-						chunkIndexMap.set(chunk, index);
+						chunkIndexMap.set(
+							chunk,
+							index | BigInt((Math.random() * 0x7fffffff) | 0)
+						);
 						index = index << ONE;
 					}
 					/**
@@ -793,7 +797,8 @@ module.exports = class SplitChunksPlugin {
 						let key =
 							chunkIndexMap.get(first) | chunkIndexMap.get(result.value);
 						while (!(result = iterator.next()).done) {
-							key = key | chunkIndexMap.get(result.value);
+							const raw = chunkIndexMap.get(result.value);
+							key = key ^ raw;
 						}
 						return key;
 					};