sdkmanager fails with RuntimeError: 304 Not Modified

Hi
when running buildozer, it runs /opt/android-sdk/tools/bin/sdkmanager directly, so I replaced it with ln -sf /usr/bin/sdkmanager /opt/android-sdk/tools/bin/sdkmanager
now while it was running, it threw this error:

# ...
# Updating SDK build tools if necessary
# Run ['/opt/android-sdk/tools/bin/sdkmanager', '--sdk_root=/opt/android-sdk', '--list']
# Cwd /opt/android-sdk
Downloading https://fdroid.gitlab.io/android-sdk-transparency-log/checksums.json.asc into /home/vagrant/.cache/sdkmanager/checksums.json.asc
Traceback (most recent call last):
  File "/opt/android-sdk/tools/bin/sdkmanager", line 33, in <module>
    sys.exit(load_entry_point('sdkmanager==0.6.8', 'console_scripts', 'sdkmanager')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/sdkmanager.py", line 1215, in main
    build_package_list(use_net=True)
  File "/usr/lib/python3/dist-packages/sdkmanager.py", line 877, in build_package_list
    download_file(checksums_url + '.asc')
  File "/usr/lib/python3/dist-packages/sdkmanager.py", line 604, in download_file
    raise RuntimeError('304 Not Modified: ' + url)
RuntimeError: 304 Not Modified: https://fdroid.gitlab.io/android-sdk-transparency-log/checksums.json.asc
# Command failed: ['/opt/android-sdk/tools/bin/sdkmanager', '--sdk_root=/opt/android-sdk', '--list']
# ...

is sdkmanager supposed to exit with non zero after a 304 response ? or is the problem somewhere else ?