Issues with RestTemplate Initialization in Spring Cloud Task

I'm currently facing a problem where the RestTemplate isn't being initialized properly when performing a Spring Cloud Task. I’ve tried searching for possible causes but haven't been able to pinpoint the root of the issue.

stacktrace

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'restTemplate' defined in demo.CoreApplication: Failed to instantiate [org.springframework.web.client.RestTemplate]: Illegal factory instance for factory method 'restTemplate'; instance: org.springframework.cloud.task.configuration.observation.ObservationCommandLineRunner
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:648)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:485)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1337)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1167)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:562)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:522)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:337)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:335)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200)
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:254)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1443)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1353)
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:904)
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:782)
	... 74 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.client.RestTemplate]: Illegal factory instance for factory method 'restTemplate'; instance: org.springframework.cloud.task.configuration.observation.ObservationCommandLineRunner
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:159)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:644)
	... 88 common frames omitted
Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.checkReceiver(DirectMethodHandleAccessor.java:197)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:99)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:140)
	... 89 common frames omitted

I'm using the following versions in my setup:

Java21
Spring Boot 3.2.7
spring-cloud-starter-task:3.1.1

Start with the RestTemplate factory method in demo.CoreApplication and the Spring Cloud Task startup path shown in the stack trace. Reproduce the task with Java 21, Spring Boot 3.2.7, and spring-cloud-starter-task 3.1.1, then trace why ObservationCommandLineRunner is used as the factory instance. Done means the task starts with RestTemplate initialized without the reported BeanCreationException.