diff --git a/studio/backend/core/training/worker.py b/studio/backend/core/training/worker.py
index 9e4fe37b5e..3b48856eb7 100644
--- a/studio/backend/core/training/worker.py
+++ b/studio/backend/core/training/worker.py
@@ -888,7 +888,9 @@ def _install_fast_path_hooks(event_queue: Any, model_name: str) -> None:
             except AttributeError:
                 pass
             ok = original()
+            ran_install = False
             if not ok:
+                ran_install = True
                 logger.info("Hook fired for %s; triggering install", gate_name)
                 _send_status(
                     event_queue,
@@ -909,10 +911,14 @@ def _install_fast_path_hooks(event_queue: Any, model_name: str) -> None:
                     gate_name,
                     ok,
                 )
-            # Even when FLA was already True, the post-available action
-            # may still have work (tilelang missing / broken tvm-ffi
-            # repair).
-            if ok and post_available_fn is not None:
+            # post_available_fn handles edge cases that ONLY occur on
+            # the gate-was-already-True path (e.g. tilelang missing
+            # while FLA is already importable, or apache-tvm-ffi on
+            # the broken-versions list while FLA otherwise works).
+            # If install_fn ran, it already chained the matching
+            # follow-up install (`_fla_install` installs tilelang too),
+            # so running post_available_fn would double-install.
+            if ok and not ran_install and post_available_fn is not None:
                 try:
                     post_available_fn(event_queue)
                 except Exception as exc:
diff --git a/studio/backend/tests/test_training_worker_flash_attn.py b/studio/backend/tests/test_training_worker_flash_attn.py
index 2cfe512be2..78cad64892 100644
--- a/studio/backend/tests/test_training_worker_flash_attn.py
+++ b/studio/backend/tests/test_training_worker_flash_attn.py
@@ -692,6 +692,10 @@ def test_hook_installs_when_gate_returns_false(monkeypatch):
 
 
 def test_hook_skips_install_when_gate_already_true(monkeypatch):
+    """When both gates are already True AND tilelang is healthy, the hook
+    must do zero install work. (Tilelang repair on the already-True path
+    is covered by test_hook_runs_tilelang_repair_when_fla_already_true.)
+    """
     fla_gate = _make_fake_gate(initial_return=True)
     conv_gate = _make_fake_gate(initial_return=True)
     _patch_iu_gates(monkeypatch, fla_gate, conv_gate)
@@ -706,6 +710,11 @@ def test_hook_skips_install_when_gate_already_true(monkeypatch):
         worker, "_ensure_tilelang_backend_unconditional", tile_install
     )
     monkeypatch.setattr(worker, "_install_package_wheel_first", conv_install)
+    # Tilelang healthy so the post_available path is a no-op (otherwise
+    # it would call tile_install, which is correct behaviour but
+    # outside the scope of this test).
+    monkeypatch.setattr(worker, "_tilelang_importable", lambda: True)
+    monkeypatch.setattr(worker, "_installed_tvm_ffi_version", lambda: "0.1.9")
     monkeypatch.delenv(worker._FAST_PATH_HOOKS_SKIP_ENV, raising=False)
 
     worker._install_fast_path_hooks(event_queue=_FakeQueue(), model_name="unsloth/Qwen3.5-2B")