Update query of field which refers to another Document throws "cannot encode objec"

[fetkod]

I have two Document objects defined like this:

`class PortFilter(Document):
linkAllowed: bool = True
nameRegexp: Optional[str]

class Port(Document):
...
portFilter: Optional[PortFilter]`

I tried to use an update query to create a new PortFilter and set port.portFilter reference like this:
port_filter = await PortFilter().create()
await Port.find(...).update(Set({Port.portFilter: port_filter}))

But it throws the following exception:
"cannot encode object: PortFilter(id=ObjectId('63b93e38e294883bae6ad9f2'), linkAllowed=True, nameRegexp=None), of type: <class 'PortFilter'>

I can update other fields which are not references to other Documents.
Is there anyway around this or is it a limitation in Beanie?
Note that support for relations using Link was introduced after I started using Beanie and I have not had time to try it out yet.