Python error related to srsly.msgpack._unpacker.unpackb

Question

When I try to import a spacy Language model I got the follow exception:

  File "D:\anaconda3\lib\site-packages\spacy\language.py", line 1037, in __call__
    doc = self._ensure_doc(text)
  File "D:\anaconda3\lib\site-packages\spacy\language.py", line 1130, in _ensure_doc
    return Doc(self.vocab).from_bytes(doc_like)
  File "spacy\tokens\doc.pyx", line 1359, in spacy.tokens.doc.Doc.from_bytes
  File "D:\anaconda3\lib\site-packages\srsly\_msgpack_api.py", line 27, in msgpack_loads
    msg = msgpack.loads(data, raw=False, use_list=use_list)
  File "D:\anaconda3\lib\site-packages\srsly\msgpack\__init__.py", line 79, in unpackb
    return _unpackb(packed, **kwargs)
  File "srsly\msgpack\_unpacker.pyx", line 199, in srsly.msgpack._unpacker.unpackb
srsly.msgpack.exceptions.ExtraData: unpack(b) received extra data.
127.0.0.1 - - [20/Jan/2024 15:36:18] "POST / HTTP/1.1" 500 -

Now some mentions:

• if I load the model only "locally" it works perfect (let's say I call the function my_func() that loads the model and use it - works fine), BUT the problem appear if I call the function my_func() via Flask: I have a running local server, and when I press a button, the my_func() is called to process some text - here appear the problem
• spacy version is 3.7.2, flask version is 2.2.2, srsly version is 2.4.8, msgpack version is 1.0.7
• here is the Flask code for that call the function (after a file is uploaded, it take the file text and process it via my_func()):

@app.route('/', methods=['GET', 'POST'])
def upload_file():
    if request.method == 'POST':
        print(request.files)
        if 'file' not in request.files:
            flash('No file part')
            return redirect(request.url)
        file = request.files['file']
        
        if file.filename == '':
            flash('No selected file')
            return render_template('index.html')
            
        # acces the file
        file_name = file.filename
        file_content = file.read()
        
        # do something with file's text
        result = my_func(file_content)
        flash(result)

    return render_template('index.html')

I tried many ways to import the spacy model: from a binary final with pickle, from the model folder created with nlp_model.to_disk(), or to create it directly every time: spacy.load("en_core_web_sm")

AGAIN, if I run without Flask (just to test function my_func() it works perfect, no error)