SpringBoot Reactive Health Indicators can't be added to health groups

Spring Boot 4.0.0

I tried to add the ReactiveMongoHealthIndicator to a health group (with management.endpoint.health.group.liveness.include: mongo)

The app won't start with NoSuchHealthContributorException error.

If I set management.endpoint.health.validate-group-membership to false, the app starts, but the HealthIndicator is not part of the health group.

I then debugged the HealthEndpointGroupMembershipValidator and saw, that only non reactive HealthIndicator are included.

I was able to temporarily fix it, by defining a normal MongoHealthIndicator bean.