diff --git a/packages/adt-flow/src/service.ts b/packages/adt-flow/src/service.ts
index d022d4c8..537e8cb6 100644
--- a/packages/adt-flow/src/service.ts
+++ b/packages/adt-flow/src/service.ts
@@ -242,11 +242,18 @@ function groupEntries(entries: readonly TransportSourceManifestEntry[]): Array<{
     );
 }
 
+const ACTIVE_VERSION_ID = '00000';
+
+function isMutableVersion(versionId: string): boolean {
+  return versionId === ACTIVE_VERSION_ID;
+}
+
 function descriptorSelectionMatches(
   descriptor: ObjectDescriptor,
   component: string,
   version: SourceVersionRef,
 ): boolean {
+  if (isMutableVersion(version.id)) return false;
   return descriptor.selections.some(
     (selection) =>
       selection.component === component &&
@@ -368,7 +375,10 @@ async function exactHeadFastPath(
     if (
       !descriptor ||
       descriptor.configDigest !== configDigest ||
-      descriptor.formatDigest !== formatDigest
+      descriptor.formatDigest !== formatDigest ||
+      descriptor.selections.some((selection) =>
+        isMutableVersion(selection.versionId),
+      )
     ) {
       return undefined;
     }
diff --git a/packages/adt-flow/tests/service.test.ts b/packages/adt-flow/tests/service.test.ts
index 4db5ff6b..cc2861ff 100644
--- a/packages/adt-flow/tests/service.test.ts
+++ b/packages/adt-flow/tests/service.test.ts
@@ -497,6 +497,89 @@ describe('transport checkout', () => {
     ).toBe('source indexed\n');
   });
 
+  it('re-reads an indexed active 00000 head instead of reusing it', async () => {
+    const workspace = await root();
+    let current = manifest(
+      'modified',
+      version('before'),
+      version('00000'),
+      'DEVK900001',
+    );
+    const ports = dependencies(() => current);
+    let liveSource = 'source first\n';
+    ports.readSource.mockImplementation(async () => liveSource);
+    const flow = createAdtFlowService(ports);
+    await flow.checkout({
+      root: workspace,
+      transports: ['DEVK900001'],
+      config,
+    });
+    ports.readSource.mockClear();
+    ports.loadObject.mockClear();
+    liveSource = 'source second\n';
+    current = manifest(
+      'modified',
+      version('before'),
+      version('00000'),
+      'DEVK900002',
+    );
+
+    const result = await flow.checkout({
+      root: workspace,
+      transports: ['DEVK900002'],
+      config,
+    });
+
+    expect(result.fastPath).toBe('none');
+    expect(result.sapCalls).toEqual({ manifest: 1, metadata: 1, source: 1 });
+    expect(ports.loadObject).toHaveBeenCalledTimes(1);
+    expect(result.changed).toEqual(['src/feature/zcl_sample.clas.abap']);
+    expect(
+      await readFile(
+        join(workspace, 'src/feature/zcl_sample.clas.abap'),
+        'utf8',
+      ),
+    ).toBe('source second\n');
+  });
+
+  it('does not repeat an active 00000 head through the exact-head fast path', async () => {
+    const workspace = await root();
+    const ports = dependencies(() =>
+      manifest('modified', version('before'), version('00000')),
+    );
+    let liveSource = 'source first\n';
+    ports.readSource.mockImplementation(async () => liveSource);
+    const flow = createAdtFlowService(ports);
+    await flow.checkout({
+      root: workspace,
+      transports: ['DEVK900001'],
+      config,
+    });
+
+    const unchanged = await flow.checkout({
+      root: workspace,
+      transports: ['DEVK900001'],
+      config,
+    });
+    expect(unchanged.fastPath).toBe('none');
+    expect(unchanged.changed).toEqual([]);
+
+    liveSource = 'source second\n';
+    const changed = await flow.checkout({
+      root: workspace,
+      transports: ['DEVK900001'],
+      config,
+    });
+    expect(changed.fastPath).toBe('none');
+    expect(changed.changed).toEqual(['src/feature/zcl_sample.clas.abap']);
+    expect(
+      await readFile(
+        join(workspace, 'src/feature/zcl_sample.clas.abap'),
+        'utf8',
+      ),
+    ).toBe('source second\n');
+  });
+
   it('preserves an indexed object as the base of a later parent-attributed task', async () => {
     const workspace = await root();
     let current = manifest(