bibtex "duplicate label for keys" warning

[snastase]

Getting a weird bibtex warning about "duplicate label for keys" that triggers an error in the build... (maybe ignore?)

Traceback (most recent call last):
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/site-packages/Sphinx-2.4.3-py3.8.egg/sphinx/cmd/build.py", line 276, in build_main
    app.build(args.force_all, filenames)
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/site-packages/Sphinx-2.4.3-py3.8.egg/sphinx/application.py", line 349, in build
    self.builder.build_update()
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/site-packages/Sphinx-2.4.3-py3.8.egg/sphinx/builders/__init__.py", line 297, in build_update
    self.build(to_build,
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/site-packages/Sphinx-2.4.3-py3.8.egg/sphinx/builders/__init__.py", line 311, in build
    updated_docnames = set(self.read())
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/contextlib.py", line 120, in __exit__
    next(self.gen)
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/site-packages/Sphinx-2.4.3-py3.8.egg/sphinx/util/logging.py", line 219, in pending_warnings
    memhandler.flushTo(logger)
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/site-packages/Sphinx-2.4.3-py3.8.egg/sphinx/util/logging.py", line 184, in flushTo
    logger.handle(record)
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/logging/__init__.py", line 1587, in handle
    self.callHandlers(record)
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/logging/__init__.py", line 1649, in callHandlers
    hdlr.handle(record)
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/logging/__init__.py", line 946, in handle
    rv = self.filter(record)
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/logging/__init__.py", line 807, in filter
    result = f.filter(record)
  File "/Users/snastase/miniconda3/envs/handbook/lib/python3.8/site-packages/Sphinx-2.4.3-py3.8.egg/sphinx/util/logging.py", line 406, in filter
    raise SphinxWarning(message)
sphinx.errors.SphinxWarning: duplicate label for keys nastase2020keep and samuel_a_nastase_2020_3677090

Warning, treated as error:
duplicate label for keys nastase2020keep and samuel_a_nastase_2020_3677090
make[1]: *** [html] Error 2
make: *** [html] Error 2