diff --git a/src/ocrmypdf/_concurrent.py b/src/ocrmypdf/_concurrent.py
index 5f27b9cf..b944a881 100644
--- a/src/ocrmypdf/_concurrent.py
+++ b/src/ocrmypdf/_concurrent.py
@@ -8,7 +8,7 @@ from __future__ import annotations
 import threading
 from abc import ABC, abstractmethod
 from collections.abc import Iterable
-from typing import Callable, TypeVar
+from typing import Any, Callable, TypeVar
 
 from ocrmypdf._progressbar import NullProgressBar, ProgressBar
 
@@ -19,6 +19,10 @@ def _task_noop(*_args, **_kwargs):
     return
 
 
+def _task_finished_noop(_result: Any, pbar: ProgressBar):
+    pbar.update()
+
+
 class Executor(ABC):
     """Abstract concurrent executor."""
 
@@ -66,7 +70,7 @@ class Executor(ABC):
         if not worker_initializer:
             worker_initializer = _task_noop
         if not task_finished:
-            task_finished = _task_noop
+            task_finished = _task_finished_noop
         if not task:
             task = _task_noop
 
diff --git a/src/ocrmypdf/optimize.py b/src/ocrmypdf/optimize.py
index a1bb2b33..004b42d7 100644
--- a/src/ocrmypdf/optimize.py
+++ b/src/ocrmypdf/optimize.py
@@ -376,7 +376,7 @@ def _produce_jbig2_images(
                 options.jbig2_threshold,
             )
 
-    def jbig2_single_args(root, groups: dict[int, list[XrefExt]]):
+    def jbig2_single_args(root: Path, groups: dict[int, list[XrefExt]]):
         for group, xref_exts in groups.items():
             prefix = f'group{group:08d}'
             # Second loop is to ensure multiple images per page are unpacked