Hi, can anyone try to help me.

i have model DOCUMENTS with "Files" as many2many field.

and model FILES with "Document" as many2one field.

i tried generation of x count FILES for each document and connect them to the Document Model.

this error occurs after changing some other values and tried to save the changes

and i get 

Traceback (most recent call last):
  File "/opt/odoo/odoo/api.py", line 989, in get
    cache_value = field_cache[record._ids[0]]
                  ~~~~~~~~~~~^^^^^^^^^^^^^^^^
KeyError: 107

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/odoo/odoo/fields.py", line 1160, in __get__
    value = env.cache.get(record, self)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/api.py", line 996, in get
    raise CacheMiss(record, field)
odoo.exceptions.CacheMiss: 'dss.ads(107,).contract_need_media'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/odoo/odoo/http.py", line 1591, in _serve_db
    return service_model.retrying(self._serve_ir_http, self.env)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/service/model.py", line 133, in retrying
    result = func()
             ^^^^^^
  File "/opt/odoo/odoo/http.py", line 1618, in _serve_ir_http
    response = self.dispatcher.dispatch(rule.endpoint, args)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/http.py", line 1822, in dispatch
    result = self.request.registry['ir.http']._dispatch(endpoint)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/addons/base/models/ir_http.py", line 154, in _dispatch
    result = endpoint(**request.params)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/http.py", line 697, in route_wrapper
    result = endpoint(self, *args, **params_ok)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/addons/web/controllers/dataset.py", line 42, in call_kw
    return self._call_kw(model, method, args, kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/addons/web/controllers/dataset.py", line 33, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/api.py", line 466, in call_kw
    result = _call_kw_multi(method, model, args, kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/api.py", line 453, in _call_kw_multi
    result = method(recs, *args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/addons/mail/models/mail_thread.py", line 312, in write
    self._track_prepare(self._fields)
  File "/opt/odoo/addons/mail/models/mail_thread.py", line 518, in _track_prepare
    values.setdefault(fname, record[fname])
                             ~~~~~~^^^^^^^
  File "/opt/odoo/odoo/models.py", line 5904, in __getitem__
    return self._fields[key].__get__(self, type(self))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/fields.py", line 2801, in __get__
    return super().__get__(records, owner)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/fields.py", line 1186, in __get__
    recs._fetch_field(self)
  File "/opt/odoo/odoo/models.py", line 3194, in _fetch_field
    self._read(fnames)
  File "/opt/odoo/odoo/models.py", line 3304, in _read
    field.read(fetched)
  File "/opt/odoo/odoo/fields.py", line 4757, in read
    order_by = comodel._generate_order_by(None, wquery)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/models.py", line 4568, in _generate_order_by
    order_by_elements = self._generate_order_by_inner(self._table, order_spec, query)
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/odoo/odoo/models.py", line 4534, in _generate_order_by_inner
    raise ValueError("Invalid field %r on model %r" % (order_field, self._name))
ValueError: Invalid field 'id' on model '_unknown'

The above server error caused the following client error:
null

i not know how to solve and not find any point to look deeper

maybe anyone can help