faust Record does not deserialize avro Union type correctly - avro

Question

I'm using faust-streaming and python-schema-registry-client to serialize faust.Record classes to avro.
When I try to deserialize a Union of two complex types however faust cannot reconstruct the correct records and only presents a dictionary instead of a faust.Record class.
I have the following code and schema:
schema_union = schema.AvroSchema({
'type': 'record',
'name': 'UnionRecord',
'fields': [
{
'name': 'entity',
'type': [
'null',
{
'name': 'company',
'type': 'record',
'fields': [
{'name': 'name_company', 'type': 'string'},
]
},
{
'name': 'person',
'type': 'record',
'fields': [
{'name': 'name_person', 'type': 'string'},
]
}
]
}
]
})
client = SchemaRegistryClient(url='http://localhost:8081')
faust_serializer_union = FaustSerializer(client, 'schema-union', schema_union)
class Company(faust.Record):
name_company: str
class Person(faust.Record):
name_person: str
class UnionRecord(
faust.Record,
validation=True,
serializer=faust_serializer_union
):
entity: Optional[Union[Company, Person]] # Union is typing.Union
record = UnionRecord(entity=Company(name_company='name'))
If I now try to serialize record and then deserialize it:
out = record.dumps() # == b'\x00\x00\x00\x00\x13\x02\x08name'
UnionRecord.loads(out)
I get this:
<UnionRecord: entity={'name_company': 'name'}>
Whereas I expect to get this:
<UnionNoneRecord: entity=<Company: name_company='name'>>
If I remove the Union type and alter the schema so that I can have a faust.Record that has only this field: Optional[Company], I do get the correct deserialization.