Jupyter Notebook "stalling" on Windows 10

Notebook
1

As of 1-2 weeks ago, a notebook I am developing has started to pause in mid flow. It is not in a compute-intensive step and there appears to be no pattern as to where is pauses.
By pause I mean the current step has In [*]

I am getting some console output which has errors (see below)
I am now fully up to date on packages but the error started before I updated all

Thank you

Exception in callback None()
handle: <Handle cancelled>
Traceback (most recent call last):
  File "C:\Users\<user>\AppData\Local\Programs\Python\Python311\Lib\asyncio\events.py", line 80, in _run
    self._context.run(self._callback, *self._args)
  File "C:\Users\<user>\AppData\Roaming\Python\Python311\site-packages\tornado\platform\asyncio.py", line 192, in _handle_events
    handler_func(fileobj, events)
  File "C:\Users\<user>\AppData\Roaming\Python\Python311\site-packages\tornado\iostream.py", line 695, in _handle_events
    self._handle_write()
  File "C:\Users\<user>\AppData\Roaming\Python\Python311\site-packages\tornado\iostream.py", line 965, in _handle_write
    self._write_buffer.advance(num_bytes)
  File "C:\Users\<user>\AppData\Roaming\Python\Python311\site-packages\tornado\iostream.py", line 182, in advance
    assert 0 < size <= self._size
           ^^^^^^^^^^^^^^^^^^^^^^
AssertionError
[I 11:47:52.453 NotebookApp] Starting buffering for 130b71b0-f5db-4413-a8b6-c5d5dc141e96:aa6db31b0af84030a8909fbeee721522
[I 11:47:53.836 NotebookApp] Restoring connection for 130b71b0-f5db-4413-a8b6-c5d5dc141e96:aa6db31b0af84030a8909fbeee721522
[I 11:47:53.836 NotebookApp] Replaying 80 buffered messages
[I 11:49:46.565 NotebookApp] Saving file at /<company>/<division>/Python/Production 2023 v13-Copy1.ipynb
[I 11:51:46.575 NotebookApp] Saving file at /<company>/<division>/Python/Production 2023 v13-Copy1.ipynb
[I 11:55:46.577 NotebookApp] Saving file at /<company>/<division>/Python/Production 2023 v13-Copy1.ipynb
2

I have seen advice to rollback tornado. What version should I rollback to? Currently on 6.3.2

I need to stay on pip and not move to Anaconda as suggested elsewhere. Full listing below.

Package Version

anyio 3.7.1
argon2-cffi 21.3.0
argon2-cffi-bindings 21.2.0
arrow 1.2.3
asttokens 2.2.1
attrs 23.1.0
backcall 0.2.0
beautifulsoup4 4.12.2
bleach 6.0.0
cffi 1.15.1
colorama 0.4.6
comm 0.1.3
debugpy 1.6.7
decorator 5.1.1
defusedxml 0.7.1
entrypoints 0.4
et-xmlfile 1.1.0
executing 1.2.0
fastjsonschema 2.17.1
fqdn 1.5.1
greenlet 2.0.2
idna 3.4
ipykernel 6.24.0
ipython 8.14.0
ipython-genutils 0.2.0
isoduration 20.11.0
jedi 0.18.2
Jinja2 3.1.2
jsonpointer 2.4
jsonschema 4.17.3
jupyter_client 8.3.0
jupyter_core 5.3.1
jupyter-events 0.6.3
jupyter_server 2.7.0
jupyter_server_terminals 0.4.4
jupyterlab-pygments 0.2.2
MarkupSafe 2.1.1
matplotlib-inline 0.1.6
mistune 3.0.1
nbclassic 1.0.0
nbclient 0.8.0
nbconvert 7.7.2
nbformat 5.9.1
nest-asyncio 1.5.6
notebook 6.5.4
notebook_shim 0.2.3
numpy 1.25.1
openpyxl 3.1.2
overrides 7.3.1
packaging 23.1
pandas 2.0.3
pandocfilters 1.5.0
parso 0.8.3
pickleshare 0.7.5
pip 23.2
platformdirs 3.9.1
prometheus-client 0.17.1
prompt-toolkit 3.0.39
psutil 5.9.5
pure-eval 0.2.2
pycparser 2.21
Pygments 2.15.1
pyodbc 4.0.39
pyrsistent 0.19.3
python-dateutil 2.8.2
python-json-logger 2.0.4
pytz 2023.3
pywin32 306
pywinpty 2.0.11
PyYAML 6.0.1
pyzmq 25.1.0
rfc3339-validator 0.1.4
rfc3986-validator 0.1.1
Send2Trash 1.8.2
setuptools 68.0.0
six 1.16.0
sniffio 1.3.0
soupsieve 2.4.1
SQLAlchemy 2.0.19
stack-data 0.6.2
terminado 0.17.1
tinycss2 1.2.1
tornado 6.3.2
traitlets 5.9.0
typing_extensions 4.7.1
tzdata 2023.3
uri-template 1.3.0
wcwidth 0.2.6
webcolors 1.13
webencodings 0.5.1
websocket-client 1.6.1