"AttributeError: 'ForkAwareLocal' object has no attribute 'connection'" even with Process.join()

I'm writing a script for comparing many DNA genomes with each other, and I'm trying to use multiprocessing to have it run faster. All the processes are appending to a common list, genome_score_avgs.

This is my main process:

if __name__ == "__main__":
    start = time.perf_counter()
    with Manager() as manager:
        genome_score_avgs = manager.list()
        processes = [Process(target=compareGenomes, args=(chunk, genome_score_avgs,)) for chunk in divideGenomes('TEST_DIR')]
        for p in processes:
            p.start()
        for p in processes:
            p.join()
    print(genome_score_avgs)
    print(*createTimeline(genome_score_avgs), sep='\n')
    print(f'Finished in {time.perf_counter() - start} seconds')

This is the error that I'm getting:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/managers.py", line 801, in _callmethod
    conn = self._tls.connection
AttributeError: 'ForkAwareLocal' object has no attribute 'connection'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/ayushpal/Coding/PythonStuff/C4DInter/main.py", line 59, in <module>
    print(*createTimeline(genome_score_avgs), sep='\n')
  File "/Users/ayushpal/Coding/PythonStuff/C4DInter/main.py", line 42, in createTimeline
    min_score = min(score_avgs, key=lambda x: x[2])
  File "<string>", line 2, in __getitem__
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/managers.py", line 805, in _callmethod
    self._connect()
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/managers.py", line 792, in _connect
    conn = self._Client(self._token.address, authkey=self._authkey)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/connection.py", line 507, in Client
    c = SocketClient(address)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/connection.py", line 635, in SocketClient
    s.connect(address)
FileNotFoundError: [Errno 2] No such file or directory
<ListProxy object, typeid 'list' at 0x7fc04ea36bb0; '__str__()' failed>

I read in a similar Stack Overflow question that the main process is ending earlier than the other processes, which destroys the shared list, and that I should use p.join() for all the processes. This is what I'm doing , however, it's still giving the same error. What should I do?

EDIT 1: this is the code for CompareGenomes():

def compareGenomes(genome_pairings, genome_score_avgs):
    scores = []
    for genome1, genome2 in genome_pairings:
        print(genome1, genome2)
        for i, seq in enumerate(genome1.protein_seqs):
            for j, seq2 in enumerate(genome2.protein_seqs[i::]):
                alignment = align.globalxx(seq, seq2)
                scores.append(alignment)
        top_scores = []

        for i in range(len(genome1.protein_seqs)):
            top_scores.append(max(scores, key=lambda x: x[0][2] / len(x[0][1])))
            scores.remove(max(scores, key=lambda x: x[0][2] / len(x[0][1])))

        avg_score = sum([i[0][2] / len(i[0][1]) for i in top_scores]) / len(top_scores)

        with open(f'alignments/{genome1.name}x{genome2.name}.txt', 'a') as file:
            file.writelines([format_alignment(*i[0]) for i in top_scores])
        genome_score_avgs.append((genome1, genome2, avg_score))