[Firebase integration] Google Analytics double counts iOS revenue

Is anybody here successfully using the RCxFirebase integration and getting correct revenue data in Google Analytics?

I have the following problem: Revenue shown in Google Analytics seems to be counted double.

For Android, I can prevent Firebase from automatically collecting revenue data via “Firebase > Project settings > Integrations > Unlink Google Play”. Then Android is fine.

For iOS, however, this is not possible. Even without the RC integration, revenue is already show in Analytics and with the integration it is twice as high…

FYI I am using this Firebase plugin for my Capacitor app:
https://github.com/capawesome-team/capacitor-firebase/tree/main/packages/analytics

...and I am using the following code (where `userId` is the user’s UUID within my app):

Capacitor.Plugins.FirebaseAnalytics.getAppInstanceId().then(result => {
    Purchases.setAttributes({$firebaseAppInstanceId: result.appInstanceId});
});

Capacitor.Plugins.FirebaseAnalytics.setUserId({userId: userId});

Purchases.logIn(userId);

Also, I have already contacted the plugin developer and Firebase and RevenueCat support and no one had an idea...