Micronaut RxJava2 Client Read Timeout even when response was received

Question

i have a very strange behaviour. I to a simple call on a RxHttpClient and the logs shows that i get a fine response

2021-10-25 14:32:54,627 [default-nioEventLoopGroup-1-3] DEBUG i.m.h.client.netty.DefaultHttpClient - Sending HTTP POST to https://myapp.authentication.eu10.hana.ondemand.com/oauth/token
2021-10-25 14:32:55,028 [default-nioEventLoopGroup-1-3] DEBUG i.m.h.client.netty.DefaultHttpClient - Received response 200 from https://myapp.authentication.eu10.hana.ondemand.com/oauth/token

But for some reason its "not forwarded" to the client. So after 30 Sek i get a read timeout

2021-10-25 14:33:25,550 [io-executor-thread-2] ERROR d.b.commerce.pinfo.sap.cps.MyAPI- Failed to renew token
io.micronaut.http.client.exceptions.ReadTimeoutException: Read Timeout
    at io.micronaut.http.client.exceptions.ReadTimeoutException.<clinit>(ReadTimeoutException.java:26)
    at io.micronaut.http.client.netty.DefaultHttpClient.lambda$null$38(DefaultHttpClient.java:1284)
    at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:94)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onError(ReactorSubscriber.java:64)
    at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124)
    at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.handleTimeout(FluxTimeout.java:295)
    at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.doTimeout(FluxTimeout.java:280)
    at reactor.core.publisher.FluxTimeout$TimeoutTimeoutSubscriber.onNext(FluxTimeout.java:419)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onNext(ReactorSubscriber.java:57)
    at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79)
    at io.micronaut.reactive.reactor.instrument.ReactorSubscriber.onNext(ReactorSubscriber.java:57)
    at reactor.core.publisher.MonoDelay$MonoDelayRunnable.propagateDelay(MonoDelay.java:271)
    at reactor.core.publisher.MonoDelay$MonoDelayRunnable.run(MonoDelay.java:286)
    at io.micronaut.reactive.reactor.instrument.ReactorInstrumentation.lambda$null$0(ReactorInstrumentation.java:62)
    at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:68)
    at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:28)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
    at java.base/java.lang.Thread.run(Thread.java:831)

Using Micronaut 3.1.1 and RxJava2 but also tried other combinations, but nothing works. I have the same setup in various other projects and it works fine there.

Regards Oli