My problem seems similar to ClassCastException in multi-module project running on Quarkus (gradle).
I am using maven, though. I can confirm the problem do not occur when using the runner or in tests. I created a sample application to reproduce the issue in https://github.com/AmsterdamFilho/quarkus-poc.
If you run the application in dev mode and execute the endpoint using swagger-ui or curl you get the Exception:
Caused by: java.lang.ClassCastException: class br.com.quarkus.poc.AnimalKindService_ClientProxy cannot be cast to class br.com.quarkus.poc.AnimalKindService (br.com.quarkus.poc.AnimalKindService_ClientProxy is in unnamed module of loader 'app'; br.com.quarkus.poc.AnimalKindService is in unnamed module of loader io.quarkus.runner.RuntimeClassLoader @7c6908d7)
The Quarkus version is 1.1.1.
Any workaround would be much appreciated.