I am using only standard modules. I reproduced the same error in the demo6.2 instance.

1- Activate all modules
2- Create product template (Produciable and Salable), go to production tab and select supply on sale
3- Create BOM
4- Create Routing
5- Assign BOM and Routing to the product
6- Create Sales Order with product and confirm the Sales Order
7- Click on Supply Stock Wizard to create production requests automatically.
8- Go to create production request and click on Wait--> then Assign--> then Run --> then Done
9- When you click done, the error will show up.

The error will show only when production request created from sales order.

Could you please share some details on how to reproduce it on an empty database?
It seems that you have some code that creates a sale move not linked to any shipment but I do not see how this is possible using standard modules. Did you have some custom code?

I got this error in 6.2 when I click done in production/productions

Traceback (most recent call last):
  File "/usr/local/lib/python39/dist-packages/trytond/wsgipy", line 117, in dispatch_request
    return endpoint(request, **requestview_args)
  File "/usr/local/lib/python39/dist-packages/trytond/protocols/dispatcherpy", line 46, in rpc
    return methodsget(requestrpc_method, _dispatch)(
  File "/usr/local/lib/python39/dist-packages/trytond/wsgipy", line 84, in auth_required
    return wrapped(*args, **kwargs)
  File "/usr/local/lib/python39/dist-packages/trytond/protocols/wrapperspy", line 159, in wrapper
    return func(request, pool, *args, **kwargs)
  File "/usr/local/lib/python39/dist-packages/trytond/protocols/dispatcherpy", line 180, in _dispatch
    result = rpcresult(meth(*c_args, **c_kwargs))
  File "/usr/local/lib/python39/dist-packages/trytond/model/modelviewpy", line 774, in wrapper
    return func(cls, records, *args, **kwargs)
  File "/usr/local/lib/python39/dist-packages/trytond/model/workflowpy", line 37, in wrapper
    result = func(cls, filtered, *args, **kwargs)
  File "/usr/local/lib/python39/dist-packages/trytond/modules/production_work/productionpy", line 135, in done
    super(Production, cls)done(productions)
  File "/usr/local/lib/python39/dist-packages/trytond/model/modelviewpy", line 774, in wrapper
    return func(cls, records, *args, **kwargs)
  File "/usr/local/lib/python39/dist-packages/trytond/model/workflowpy", line 37, in wrapper
    result = func(cls, filtered, *args, **kwargs)
  File "/usr/local/lib/python39/dist-packages/trytond/modules/production_outsourcing/productionpy", line 242, in done
    super(Production, cls)done(productions)
  File "/usr/local/lib/python39/dist-packages/trytond/model/modelviewpy", line 774, in wrapper
    return func(cls, records, *args, **kwargs)
  File "/usr/local/lib/python39/dist-packages/trytond/model/workflowpy", line 37, in wrapper
    result = func(cls, filtered, *args, **kwargs)
  File "/usr/local/lib/python39/dist-packages/trytond/modules/sale_supply_production/productionpy", line 27, in wrapper
    func(cls, productions)
  File "/usr/local/lib/python39/dist-packages/trytond/modules/sale_supply_production/productionpy", line 82, in done
    productionassign_supplied()
  File "/usr/local/lib/python39/dist-packages/trytond/modules/sale_supply_production/productionpy", line 115, in assign_supplied
    sale_lineassign_supplied(pbl[sale_lineproduct], grouping=grouping)
  File "/usr/local/lib/python39/dist-packages/trytond/modules/sale_supply/salepy", line 223, in assign_supplied
    for inv_move in moveshipmentinventory_moves:
AttributeError: 'NoneType' object has no attribute 'inventory_moves'