diff -Nurp sigal-2.3.orig/sigal/writer.py sigal-2.3/sigal/writer.py
--- sigal-2.3.orig/sigal/writer.py	2022-08-08 19:43:10.934707194 +0200
+++ sigal-2.3/sigal/writer.py	2022-08-08 19:44:57.542382532 +0200
@@ -103,7 +103,11 @@ class AbstractWriter:
             os.path.join(THEMES_PATH, 'default', 'static'),
             os.path.join(self.theme, 'static'),
         ):
-            shutil.copytree(static_path, self.theme_path, dirs_exist_ok=True)
+            # https://stackoverflow.com/a/17022146/4935114
+            orig_copystat = shutil.copystat
+            shutil.copystat = lambda x, y: x
+            shutil.copytree(static_path, self.theme_path, dirs_exist_ok=True, copy_function=shutil.copy)
+            shutil.copystat = orig_copystat
 
         if self.settings["user_css"]:
             if not os.path.exists(self.settings["user_css"]):