diff --git a/package-lock.json b/package-lock.json
index 7117787..cddaeea 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -2629,13 +2629,10 @@
       "dev": true
     },
     "node_modules/@types/node": {
-      "version": "20.12.7",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-20.12.7.tgz",
-      "integrity": "sha512-wq0cICSkRLVaf3UGLMGItu/PtdY7oaXaI/RVU+xliKVOtRna3PRY57ZDfztpDL0n11vfymMUnXv8QwYCO7L1wg==",
-      "dev": true,
-      "dependencies": {
-        "undici-types": "~5.26.4"
-      }
+      "version": "20.8.3",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-20.8.3.tgz",
+      "integrity": "sha512-jxiZQFpb+NlH5kjW49vXxvxTjeeqlbsnTAdBTKpzEdPs9itay7MscYXz3Fo9VYFEsfQ6LJFitHad3faerLAjCw==",
+      "dev": true
     },
     "node_modules/@types/normalize-package-data": {
       "version": "2.4.4",
@@ -12199,12 +12196,6 @@
         "node": ">=14.0"
       }
     },
-    "node_modules/undici-types": {
-      "version": "5.26.5",
-      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-5.26.5.tgz",
-      "integrity": "sha512-JlCMO+ehdEIKqlFxk6IfVoAUVmgz7cU7zD/h9XZ0qzeosSHmUJVOzSQvvYSYWXkFXC+IfLKSIffhv0sVZup6pA==",
-      "dev": true
-    },
     "node_modules/unicode-emoji-modifier-base": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/unicode-emoji-modifier-base/-/unicode-emoji-modifier-base-1.0.0.tgz",
diff --git a/package.json b/package.json
index ca40f1e..d96cc21 100644
--- a/package.json
+++ b/package.json
@@ -9,8 +9,8 @@
   "scripts": {
     "build": "tsc",
     "build-worker": "node worker/build.js",
-    "test": "npm run-script build-worker && node --experimental-vm-modules node_modules/jest/bin/jest.js --verbose --collectCoverage --coverageProvider=v8",
-    "test-debug": "npm run-script build-worker && node --experimental-vm-modules --inspect-brk node_modules/jest/bin/jest.js --runInBand",
+    "test": "npm run-script build-worker && node --no-experimental-fetch --experimental-vm-modules node_modules/jest/bin/jest.js --verbose --collectCoverage --coverageProvider=v8",
+    "test-debug": "npm run-script build-worker && node --no-experimental-fetch --experimental-vm-modules --inspect-brk node_modules/jest/bin/jest.js --runInBand",
     "format": "prettier --write  '*.{json,js}' 'src/**/*.{js,ts}' 'test/**/*.{js,ts}'",
     "lint": "eslint --max-warnings=0 src && prettier --check '*.{json,js}' 'src/**/*.{js,ts}' 'test/**/*.{js,ts}'",
     "prepack": "npm run-script test && npm run-script lint && npm run-script build",
@@ -110,5 +110,8 @@
   },
   "dependencies": {
     "worktop": "0.7.3"
+  },
+  "overrides": {
+    "@types/node": "20.8.3"
   }
 }
diff --git a/src/processConditionals.ts b/src/processConditionals.ts
index 0a381d1..a6a77a4 100644
--- a/src/processConditionals.ts
+++ b/src/processConditionals.ts
@@ -125,16 +125,25 @@ function esi_eval_var_in_when_tag(
   match: [String: string, ...args: string[]],
 ): string {
   const varInTag = esi_eval_var(eventData, match);
-
-  const number = parseInt(varInTag, 10);
-  if (number) {
-    return number.toString();
+  // we have to check varInTag is *actually* a number and doesn't just have leading numbers in it
+  if (strIsNumber(varInTag)) {
+    return parseInt(varInTag, 10).toString();
   } else {
     // Change to replaceAll once upgraded node
     return "'" + varInTag.replace(/'/g, "\\'") + "'";
   }
 }
 
+/**
+ * Evaluates str and returns if it *actually* is a number not just a str with leading numbers
+ *
+ * @param {string} str string to check
+ * @returns {boolean} check result
+ */
+function strIsNumber(str: string): boolean {
+  return !isNaN(Number(str));
+}
+
 /**
  * Takes a condition string and splits it into its two sides and operator
  * passes that to the tester and returns the result
diff --git a/test/esi.spec.ts b/test/esi.spec.ts
index f0d97c5..29a92b3 100644
--- a/test/esi.spec.ts
+++ b/test/esi.spec.ts
@@ -1911,3 +1911,33 @@ test("TEST 50: Multiple ESI Args make it all the way through", async () => {
     `esi_args1=1&esi_args2=2&esi_args3=3&esi_args4=4`,
   );
 });
+
+describe("TEST 51: ESI Args that lead with ints shouldn't convert to ints", () => {
+  const checks = [
+    { arg: "1719,2405", result: "first-lineage" },
+    { arg: "1719,1732", result: "second-lineage" },
+    { arg: "1719,1918", result: "third-lineage" },
+    { arg: "1719,1922", result: "forth-lineage" },
+    { arg: "1719,1926", result: "fith-lineage" },
+  ];
+
+  const url = `/esi/test-51`;
+  checks.forEach(function (check) {
+    it(check.result, async () => {
+      routeHandler.add(url, function (req, res) {
+        res.writeHead(200, esiHead);
+        res.end(`
+    first-lineage
+    second-lineage
+    third-lineage
+    forth-lineage
+    fith-lineage
+`);
+      });
+      const res = await makeRequest(`${url}?esi_lineage=${check.arg}`);
+      expect(res.ok).toBeTruthy();
+      expect(await res.text()).toEqual(check.result);
+      expect(checkSurrogate(res)).toBeTruthy();
+    });
+  });
+});