ANDROID: Local database are backed up when sync is enabled

I have a Android module containing 2 “databases”. One only local using RealmConfiguration:

val localConfig = RealmConfiguration.Builder()
val instance = Realm.getInstance(localConfig)

*** Note for the local: we install the app with empty data and we download a NAME.realm file and overwrite the initial NAME.realm created at install.

the other database is synchronized using a SyncConfiguration:

val app = App(AppConfiguration.Builder(REALM_APP_ID).build())
val syncConfig = SyncConfiguration.Builder(app.currentUser(), PARTITION).schemaVersion(1).modules(SalePointModule()).build()
val instance = Realm.getInstance(syncConfig)

Everything works fine, except for the fact that wemphasised texthen I install the app my local database seems to be backed up. A new file is stored databaseName.v9.backup.realm.

Log file : Tue Sep 21 16:22:37 2021 : Creating backup: /data/user/0/package_name/files/databaseName.v9.backup.realm
Tue Sep 21 16:22:37 2021 : Completed backup: data/user/0/package_name/files/databaseName.v9.backup.realm

I’m not sure what is the problem. It look like a client reset wich save a backup on disk, but i’m not sure why this would happens in a local database only. The backup doesnt happens without the sync logic enabled.

What SDK are you using and do you have a crash log/exception message that you can share?