Spring Boot App - Reactor Core Threads not being Stopped on Shutdown

Question

Since upgrading from Sprint Boot 2.5.14 to Spring Boot 2.7.10, I see numerous warnings on application shutdown notifying me that threads have not been properly stopped. Through testing, I discovered this was related to the usage of Schedulers in reactor-core. I was able to produce a minimal example.

Controller

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import reactor.core.publisher.Flux;
import reactor.core.scheduler.Schedulers;

@RestController
public class GreetingController {
   

    @GetMapping("/greeting")
    public Flux<Integer> greeting(@RequestParam(value = "name", defaultValue = "World") String name) {
        Flux<Integer> flux = Flux.range(0, 2)
                .publishOn(Schedulers.parallel());
        return flux;
    }
}

pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    
    <dependency>
        <groupId>io.projectreactor</groupId>
        <artifactId>reactor-core</artifactId>
    </dependency>
</dependencies>

Logs on shutdown - I see one error message for each time sample endpoint was called.

2023-04-10 11:31:40.640  WARN 24492 --- [on(8)-127.0.0.1] o.a.c.loader.WebappClassLoaderBase       : The web application [ROOT] appears to have started a thread named [parallel-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1081)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
 java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 java.lang.Thread.run(Thread.java:750)
2023-04-10 11:31:40.641  WARN 24492 --- [on(8)-127.0.0.1] o.a.c.loader.WebappClassLoaderBase       : The web application [ROOT] appears to have started a thread named [parallel-2] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1081)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
 java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 java.lang.Thread.run(Thread.java:750)
2023-04-10 11:31:40.641  WARN 24492 --- [on(8)-127.0.0.1] o.a.c.loader.WebappClassLoaderBase       : The web application [ROOT] appears to have started a thread named [parallel-3] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1081)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
 java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 java.lang.Thread.run(Thread.java:750)

Spring Boot version used: 2.7.10 (also happened in 2.7.9) JVM version (java -version): 1.8.0_333 OS and version (eg uname -a): Windows

Any ideas why the threads are not getting stopped? Any suggestions for changes so that they do? Thanks in advance for your help!