RXJava2 on Android - nested completable does not get called - kotlin

Question

I have a completable method for authentication and I want to retrieve the authenticated user details on login success.
After retrieving them, I want to call an onUserAuthenticated method.
I am doing this with a nested completable (2 levels deep), as I want to sent both the authorization token received on login and the user details to the onUserAuthenticated method.
The problem is that onUserAuthenticated never gets invoked.
class LoginViewModel(val emailAuthentication: EmailAuthentication) : ViewModel() {
val email = MutableLiveData<String>()
val password = MutableLiveData<String>()
fun login() {
emailAuthentication.login(email = email.value!!, password = password.value!!)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe({
Timber.d("User $email logged in")
}, { error ->
Timber.e(error, "Error logging in $email")
})
}
}
class EmailAuthenticationImpl(private val authentication: Authentication,
private val userRepository: UserRepository,
private val authRepository: AuthenticationRepository
) : EmailAuthentication {
override fun register(email: String, password: String): Completable {
return userRepository.register(email, password)
}
override fun login(email: String, password: String): Completable {
// some missing fields validation
return authRepository.login(email, password)
.flatMapCompletable { token ->
userRepository.getCurrentUser()
.flatMapCompletable {
Completable.defer {
// FIXME this never gets invoked
authentication.onUserAuthenticated(AuthType.EMAIL, it, token)
Completable.complete()
}
}
}
}
I tried putting Completable.defer also only before userRepository.getCurrentUser() and both before userRepository.getCurrentUser() and before authentication.onUserAuthenticated(AuthType.EMAIL, it, token), but the code is never reached.
What am I doing wrong?