diff --git a/distributed/client.py b/distributed/client.py
index bc39b956d2..415394ab17 100644
--- a/distributed/client.py
+++ b/distributed/client.py
@@ -3094,7 +3094,6 @@ async def _run(
             elif resp["status"] == "error":
                 # Exception raised by the remote function
                 _, exc, tb = clean_exception(**resp)
-                assert exc is not None
                 exc = exc.with_traceback(tb)
             else:
                 assert resp["status"] == "OK"
@@ -3250,20 +3249,8 @@ def _get_computation_code(
                     "|".join([f"(?:{mod})" for mod in ignore_modules])
                 )
             if ignore_files:
-                # Given ignore-files = [foo], match:
-                #   /path/to/foo
-                #   /path/to/foo.py[c]
-                #   /path/to/foo/bar.py[c]
-                #   \path\to\foo
-                #   \path\to\foo.py[c]
-                #   \path\to\foo\bar.py[c]
-                #   <frozen foo>
-                # Do not match files that have 'foo' as a substring,
-                # unless the user explicitly states '.*foo.*'.
-                ignore_files_or = "|".join(mod for mod in ignore_files)
                 fname_pattern = re.compile(
-                    rf".*[\\/]({ignore_files_or})([\\/]|\.pyc?$|$)"
-                    rf"|<frozen ({ignore_files_or})>$"
+                    r".*[\\/](" + "|".join(mod for mod in ignore_files) + r")([\\/]|$)"
                 )
         else:
             # stacklevel 0 or less - shows dask internals which likely isn't helpful