diff --git a/httpie/cli/utils.py b/httpie/cli/utils.py
index ad27da37f7..956dd0e9dd 100644
--- a/httpie/cli/utils.py
+++ b/httpie/cli/utils.py
@@ -1,8 +1,14 @@
 import argparse
+import sys
 from typing import Any, Callable, Generic, Iterator, Iterable, Optional, TypeVar
 
 T = TypeVar('T')
 
+# Python 3.14 added an eager _check_help() call in add_argument() that
+# validates the help string immediately (see cpython#65865). This causes
+# LazyChoices.help to invoke the getter at argument-registration time.
+_ARGPARSE_CHECKS_HELP_EAGERLY = sys.version_info >= (3, 14)
+
 
 class Manual(argparse.Action):
     def __init__(
@@ -54,7 +60,7 @@ def load(self) -> T:
         return self._obj
 
     @property
-    def help(self) -> str:
+    def help(self) -> Optional[str]:
         if self._help is None and self.help_formatter is not None:
             self._help = self.help_formatter(
                 self.load(),
diff --git a/httpie/downloads.py b/httpie/downloads.py
index 9c4b895e6f..22bf6214b7 100644
--- a/httpie/downloads.py
+++ b/httpie/downloads.py
@@ -216,12 +216,21 @@ def start(
         """
         assert not self.status.time_started
 
-        # FIXME: some servers still might sent Content-Encoding: gzip
-        # <https://github.com/httpie/cli/issues/423>
-        try:
-            total_size = int(final_response.headers['Content-Length'])
-        except (KeyError, ValueError, TypeError):
+        # When Content-Encoding is present (e.g. gzip), the `requests` library
+        # transparently decodes the response body, so the bytes written to disk
+        # will be the *decompressed* size — which typically exceeds the
+        # Content-Length value (which reflects the compressed wire size).
+        # Using Content-Length as the total size in that case would make us
+        # flag the download as incomplete even when everything is fine.
+        # See <https://github.com/httpie/cli/issues/1642>.
+        content_encoding = final_response.headers.get('Content-Encoding', '').strip()
+        if content_encoding:
             total_size = None
+        else:
+            try:
+                total_size = int(final_response.headers['Content-Length'])
+            except (KeyError, ValueError, TypeError):
+                total_size = None
 
         if not self._output_file:
             self._output_file = self._get_output_file_from_response(
diff --git a/tests/test_cli_utils.py b/tests/test_cli_utils.py
index 8041727b57..1e09b25802 100644
--- a/tests/test_cli_utils.py
+++ b/tests/test_cli_utils.py
@@ -1,7 +1,8 @@
+import sys
 import pytest
 from argparse import ArgumentParser
 from unittest.mock import Mock
-from httpie.cli.utils import LazyChoices
+from httpie.cli.utils import LazyChoices, _ARGPARSE_CHECKS_HELP_EAGERLY
 
 
 def test_lazy_choices():
@@ -69,10 +70,19 @@ def test_lazy_choices_help():
         cache=False  # for test purposes
     )
 
-    # Parser initialization doesn't call it.
-    getter.assert_not_called()
-
-    # If we don't use `--help`, we don't use it.
+    # Python 3.14 added an eager _check_help() call in add_argument() that
+    # validates the help string immediately (cpython#65865).  On 3.14+, the
+    # getter will therefore be invoked once at registration time.
+    if _ARGPARSE_CHECKS_HELP_EAGERLY:
+        getter.assert_called_once()
+        getter.reset_mock()
+        help_formatter.assert_called_once()
+        help_formatter.reset_mock()
+    else:
+        # Parser initialization must not call getter or help_formatter.
+        getter.assert_not_called()
+
+    # If we don't use `--help`, we don't use them beyond registration.
     parser.parse_args([])
     getter.assert_not_called()
     help_formatter.assert_not_called()
@@ -80,7 +90,10 @@ def test_lazy_choices_help():
     parser.parse_args(['--lazy-option', 'b'])
     help_formatter.assert_not_called()
 
-    # If we use --help, then we call it with styles
+    # If we use --help, then we call it with styles.
+    # On Python 3.14+, help_formatter was already called during registration
+    # and the cached result is reused — it should not be called again.
     with pytest.raises(SystemExit):
         parser.parse_args(['--help'])
-    help_formatter.assert_called_once_with(['a', 'b', 'c'], isolation_mode=False)
+    if not _ARGPARSE_CHECKS_HELP_EAGERLY:
+        help_formatter.assert_called_once_with(['a', 'b', 'c'], isolation_mode=False)
diff --git a/tests/test_downloads.py b/tests/test_downloads.py
index b646a0e6a5..6396693c0d 100644
--- a/tests/test_downloads.py
+++ b/tests/test_downloads.py
@@ -247,6 +247,31 @@ def test_download_resumed(self, mock_env, httpbin_both):
                 downloader.chunk_downloaded(b'45')
                 downloader.finish()
 
+    def test_download_with_content_encoding_does_not_report_incomplete(self, mock_env, httpbin_both):
+        """Regression test for https://github.com/httpie/cli/issues/1642.
+
+        When Content-Encoding (e.g. gzip) is present, the `requests` library
+        transparently decodes the body, so the bytes written to disk may exceed
+        the compressed Content-Length.  The downloader must not report the
+        download as incomplete in that case.
+        """
+        with open(os.devnull, 'w') as devnull:
+            downloader = Downloader(mock_env, output_file=devnull)
+            downloader.start(
+                final_response=Response(
+                    url=httpbin_both.url + '/',
+                    headers={
+                        'Content-Length': 5,          # compressed size
+                        'Content-Encoding': 'gzip',
+                    }
+                ),
+                initial_url='/'
+            )
+            # Simulate receiving more decompressed bytes than Content-Length.
+            downloader.chunk_downloaded(b'12345678')  # 8 bytes > 5 bytes
+            downloader.finish()
+            assert not downloader.interrupted
+
     def test_download_with_redirect_original_url_used_for_filename(self, httpbin):
         # Redirect from `/redirect/1` to `/get`.
         expected_filename = '1.json'