We have a complex configuration properties, with a list of polymorphic objects. Once parsed by Spring Boot using a @ConfigurationProperties (version 3.1.6, but the same in 3.2.0) - those polymorphic objects are deserialized as their base class, so all the inherited properties are lost.
Here is a sample project to reproduce the issue:
https://github.com/anatoliy-balakirev/spring_boot_polymorphic_properties
The test DemoApplicationTests fails, because manually loaded configuration properties (deserialized by the new ObjectMapper(new YAMLFactory())) do not match those, loaded by the Spring Boot (using the @ConfigurationProperties mechanism).
Comment From: wilkinsona
Duplicates https://github.com/spring-projects/spring-boot/issues/16900.