diff --git a/actions/setup/js/action_conclusion_otlp.test.cjs b/actions/setup/js/action_conclusion_otlp.test.cjs
index efe7daeb4f0..ff7334e0cd5 100644
--- a/actions/setup/js/action_conclusion_otlp.test.cjs
+++ b/actions/setup/js/action_conclusion_otlp.test.cjs
@@ -15,8 +15,12 @@ const { run } = req("./action_conclusion_otlp.cjs");
 // Shared mock function — patched onto the module exports in beforeEach
 const mockSendJobConclusionSpan = vi.fn();
 
+/** Env vars read by this module — cleared before each test */
+const MANAGED_ENV_VARS = ["OTEL_EXPORTER_OTLP_ENDPOINT", "INPUT_JOB_NAME", "INPUT_JOB-NAME", "GITHUB_AW_OTEL_JOB_START_MS"];
+
 describe("action_conclusion_otlp.cjs", () => {
-  let originalEnv;
+  /** @type {Record<string, string | undefined>} */
+  let originalEnv = {};
 
   beforeEach(() => {
     vi.clearAllMocks();
@@ -24,43 +28,21 @@ describe("action_conclusion_otlp.cjs", () => {
     mockSendJobConclusionSpan.mockResolvedValue(undefined);
     // Patch the shared CJS exports object — run() accesses this at call time
     sendOtlpModule.sendJobConclusionSpan = mockSendJobConclusionSpan;
-
-    originalEnv = {
-      OTEL_EXPORTER_OTLP_ENDPOINT: process.env.OTEL_EXPORTER_OTLP_ENDPOINT,
-      INPUT_JOB_NAME: process.env.INPUT_JOB_NAME,
-      "INPUT_JOB-NAME": process.env["INPUT_JOB-NAME"],
-      GITHUB_AW_OTEL_JOB_START_MS: process.env.GITHUB_AW_OTEL_JOB_START_MS,
-    };
-    delete process.env.OTEL_EXPORTER_OTLP_ENDPOINT;
-    delete process.env.INPUT_JOB_NAME;
-    delete process.env["INPUT_JOB-NAME"];
-    delete process.env.GITHUB_AW_OTEL_JOB_START_MS;
+    originalEnv = Object.fromEntries(MANAGED_ENV_VARS.map(key => [key, process.env[key]]));
+    MANAGED_ENV_VARS.forEach(key => delete process.env[key]);
   });
 
   afterEach(() => {
     vi.restoreAllMocks();
     sendOtlpModule.sendJobConclusionSpan = originalSendJobConclusionSpan;
-
-    if (originalEnv.OTEL_EXPORTER_OTLP_ENDPOINT !== undefined) {
-      process.env.OTEL_EXPORTER_OTLP_ENDPOINT = originalEnv.OTEL_EXPORTER_OTLP_ENDPOINT;
-    } else {
-      delete process.env.OTEL_EXPORTER_OTLP_ENDPOINT;
-    }
-    if (originalEnv.INPUT_JOB_NAME !== undefined) {
-      process.env.INPUT_JOB_NAME = originalEnv.INPUT_JOB_NAME;
-    } else {
-      delete process.env.INPUT_JOB_NAME;
-    }
-    if (originalEnv["INPUT_JOB-NAME"] !== undefined) {
-      process.env["INPUT_JOB-NAME"] = originalEnv["INPUT_JOB-NAME"];
-    } else {
-      delete process.env["INPUT_JOB-NAME"];
-    }
-    if (originalEnv.GITHUB_AW_OTEL_JOB_START_MS !== undefined) {
-      process.env.GITHUB_AW_OTEL_JOB_START_MS = originalEnv.GITHUB_AW_OTEL_JOB_START_MS;
-    } else {
-      delete process.env.GITHUB_AW_OTEL_JOB_START_MS;
-    }
+    MANAGED_ENV_VARS.forEach(key => {
+      const value = originalEnv[key];
+      if (value === undefined) {
+        delete process.env[key];
+      } else {
+        process.env[key] = value;
+      }
+    });
   });
 
   it("should export run as a function", () => {
@@ -177,6 +159,14 @@ describe("action_conclusion_otlp.cjs", () => {
 
         expect(mockSendJobConclusionSpan).toHaveBeenCalledWith("gh-aw.job.conclusion", { startMs: undefined });
       });
+
+      it("should pass startMs: undefined when GITHUB_AW_OTEL_JOB_START_MS is a negative number", async () => {
+        process.env.GITHUB_AW_OTEL_JOB_START_MS = "-1000";
+
+        await run();
+
+        expect(mockSendJobConclusionSpan).toHaveBeenCalledWith("gh-aw.job.conclusion", { startMs: undefined });
+      });
     });
   });
 
diff --git a/actions/setup/js/safe_outputs_handlers.test.cjs b/actions/setup/js/safe_outputs_handlers.test.cjs
index fa128edcec3..a45b7ef1f29 100644
--- a/actions/setup/js/safe_outputs_handlers.test.cjs
+++ b/actions/setup/js/safe_outputs_handlers.test.cjs
@@ -522,6 +522,7 @@ describe("safe_outputs_handlers", () => {
       });
 
       process.env.GITHUB_BASE_REF = "master";
+      process.env.GITHUB_HEAD_REF = "feature/test-change";
       process.env.GITHUB_REF_NAME = "feature/test-change";
       try {
         const result = await handlers.createPullRequestHandler({
@@ -543,6 +544,7 @@ describe("safe_outputs_handlers", () => {
         );
       } finally {
         delete process.env.GITHUB_BASE_REF;
+        delete process.env.GITHUB_HEAD_REF;
         delete process.env.GITHUB_REF_NAME;
       }
     });