Firebase Remote Config A/B testing shows no results

We've configured remote config Firebase A/B testing and everything works fine. The UI changes and logs show a/b test is applied. Though, we're not getting any data in Firebase.

We've checked the following topics and these seem to be implemented correctly.

• AB testing config applied but firebase console show 0 users
• Firebase Remote Config A/B testing shows no results after 24 hours

Our current code:

 val configSettings = FirebaseRemoteConfigSettings.Builder()
                .setMinimumFetchIntervalInSeconds(0)
                .setFetchTimeoutInSeconds(120)
                .build()
        remoteConfig.setConfigSettingsAsync(configSettings)
        remoteConfig.fetchAndActivate().addOnCanceledListener {
             ...
        }.addOnCompleteListener {
             ...
        }

Our activation event is trigged via GTM. Maybe we're missing something?

Thanks for your help!