The code that was causing this problem looked something like:

--
def emit(self, record):
  ...
  response = requests.post(...)
  if not response.ok:
     self.handleError(record)
  ...
--

In this case, something does apparently go wrong, but it doesn't actually involve an exception.

I assume that I'm not the only person in the world dealing with a code base where handleError was misused like this.

Here's some evidence that this is true: https://www.programcreek.com/python/example/619/logging.Handler (search for handleError in the page)