Same issue on Window 10 and macOS Catalina with Python 3.8.0.
Here is the error I get on Windows 10:

C:\Users\x>py -3.8
Python 3.8.0 (tags/v3.8.0:fa919fd, Oct 14 2019, 19:37:50) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from multiprocessing import get_context
>>>
>>> class A(object):
...     def __init__(self):
...         self.pool = get_context(None).Pool(2)
...
>>> solver=A()
>>> quit()
Process SpawnPoolWorker-2:
Error in atexit._run_exitfuncs:
Process SpawnPoolWorker-1:
Traceback (most recent call last):
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\process.py", line 313, in _bootstrap
    self.run()
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\pool.py", line 114, in worker
    task = get()
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\queues.py", line 355, in get
    with self._rlock:
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\synchronize.py", line 95, in __enter__
    return self._semlock.__enter__()
Traceback (most recent call last):
KeyboardInterrupt
Traceback (most recent call last):
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\util.py", line 277, in _run_finalizers
    finalizer()
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\util.py", line 201, in __call__
    res = self._callback(*self._args, **self._kwargs)
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\pool.py", line 689, in _terminate_pool
    cls._help_stuff_finish(inqueue, task_handler, len(pool))
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\pool.py", line 674, in _help_stuff_finish
    inqueue._rlock.acquire()
KeyboardInterrupt
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\process.py", line 313, in _bootstrap
    self.run()
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\pool.py", line 114, in worker
    task = get()
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\queues.py", line 356, in get
    res = self._reader.recv_bytes()
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\connection.py", line 216, in recv_bytes
    buf = self._recv_bytes(maxlength)
  File "C:\Users\x\AppData\Local\Programs\Python\Python38\lib\multiprocessing\connection.py", line 305, in _recv_bytes
    waitres = _winapi.WaitForMultipleObjects(
KeyboardInterrupt

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