Objects not propagated to Camel Kafka 3.18.4

[Martin Pelikán]

Hi Camel experts,

I am struggling with a Kafka component and passing in parameters via
additionalProperties. I am not able to propagate an Object. I tested
only Endpoint DSL. According to the Camel docs and APIs, I am allowed
to pass in an instance of Map<String, Object>

 Camel version: 3.18.4

----Pseudocode-----

@Configuration
Class SpringConfig

@Bean(name = "autowiredMap")
public Map<String, Object> autowiredMap() {
    var map = new HashMap<String, Object>();
    map.put("testStringKey3", "testStringValue3");
    map.put("testObjectKey3", new Object());
}

-------

Class MainRoute extends RouteBuilder()

@Autowired
@Qualifier("autowiredMap")
Map<String, Object> autowiredMap;

var map = new HashMap<String, Object>();
map.put("testStringKey1", "testStringValue1");
map.put("testObjectKey1", new Object());

from(kafka(…basic configuration works)
    .schemaRegistryURL(http://original.com)
    .additionalProperties(map)
    .additionalProperties("testStringKey2", "testStringValue2")
    .additionalProperties("testObjectKey1", new Object())
    .additionalProperties("schema.registry.url", http://overwritten.com)
    .additionalProperties(autowiredMap)...

Expected:

All properties from all additionalProperties methods are propagated to
the Kafka Properties configuration object.

In reality, Properties will contain the following:
schema.registry.url=http://overwritten.com
testStringKey1=testStringValue1
testStringKey2=testStringValue2

Non-string values are not propagated at all. Values from autowired Map
are not propagated at all. Autowired map is treated as
additionalProperties.autowiredMap=HashMap@123456

I can see those String values being added to the Kafka Endpoint URI:
kafka://additionalProperties.testStringKey1=xxx&additionalProperties.testStringKey2=xxx&additionalProperties.schema.registr.url=xxx..

Is it a bug in Camel or did I understand the documentation wrong? I
can prepare a test case later

Best regards,

Martin