Resource not closed warning with rest client

This is a bit hard to reproduce for me. Like in #10804 I am doing remote calls via the MP Rest Client

 @Inject
  @RestClient
  RbacServer rbac;
...
   try {
      result = getRbacInfo(user.getRawRhIdHeader());
    } catch (Throwable e) {
...

  @CacheResult(cacheName = "rbac-cache")
  RbacRaw getRbacInfo(String xrhidHeader)  {
    RbacRaw result;
    result = rbac.getRbacInfo("policies", xrhidHeader);  // <---
    return result;
  }

And I get (not always) the following in the logs:

2020-07-17 16:58:30,999 WARN [org.jbo.res.cli.jax.i18n] (Finalizer) RESTEASY004687: Closing a class org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient43Engine instance for you. Please close clients yourself.

Locally I could reproduce it now with the remote service returning a 401, but I also see that on our production instance, where I do not see any errors from the remote call.

2020-07-17 17:38:59,103 WARNING [RbacFilter] (executor-thread-1) Call to RBAC took 1301ms
2020-07-17 17:38:59,102 WARNING [com.git.ben.caf.cac.LocalAsyncCache] (Thread-13) Exception thrown during asynchronous load: java.util.concurrent.CompletionException: javax.ws.rs.WebApplicationException: Unknown error, status code 401
        at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:314)
        at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:319)
        at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1702)
        at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: javax.ws.rs.WebApplicationException: Unknown error, status code 401
        at org.jboss.resteasy.microprofile.client.DefaultResponseExceptionMapper.toThrowable(DefaultResponseExceptionMapper.java:16)
        at org.jboss.resteasy.microprofile.client.ExceptionMapping$HandlerException.mapException(ExceptionMapping.java:38)
        at org.jboss.resteasy.microprofile.client.ProxyInvocationHandler.invoke(ProxyInvocationHandler.java:151)
        at com.sun.proxy.$Proxy75.getRbacInfo(Unknown Source)
        at com.redhat.cloud.policies.app.auth.RbacFilter.getRbacInfo(RbacFilter.java:95)
        at com.redhat.cloud.policies.app.auth.RbacFilter_Subclass.getRbacInfo$$superaccessor1(RbacFilter_Subclass.zig:205)
        at com.redhat.cloud.policies.app.auth.RbacFilter_Subclass$$function$$1.apply(RbacFilter_Subclass$$function$$1.zig:33)
        at io.quarkus.arc.impl.AroundInvokeInvocationContext.proceed(AroundInvokeInvocationContext.java:54)
        at io.quarkus.cache.runtime.CacheResultInterceptor.lambda$intercept$0(CacheResultInterceptor.java:27)
        at io.quarkus.cache.runtime.caffeine.CaffeineCache$MappingSupplier.get(CaffeineCache.java:136)
        at io.quarkus.cache.runtime.caffeine.CaffeineCache.lambda$get$0(CaffeineCache.java:58)
        at com.github.benmanes.caffeine.cache.LocalAsyncCache.lambda$get$0(LocalAsyncCache.java:77)
        at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1700)
        ... 1 more

{"date":"Fri, 17 Jul 2020 15:38:57 GMT","method":"GET","uri":"/api/policies/v1.0/policies/123","acct":"901578","http_version":"HTTP/1.1","status":403,"content_length":0,"duration":1318,"user_agent":"curl/7.54.0","remote":"0:0:0:0:0:0:0:1"}
2020-07-17 17:39:09,854 WARN  [org.jbo.res.cli.jax.i18n] (Finalizer) RESTEASY004687: Closing a class org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient43Engine instance for you. Please close clients yourself.

Commenting out the @CacheResult() makes the warning/stack trace go away, but still shows the Finalizer-warning.