What should happen if a Core Data app finds the Model is newer than its?

Have an app that has a half dozen models. We created a new app version with a new model that has an additional property on one entity.

The options for the persistent store:

do {
    let options = [
        NSMigratePersistentStoresAutomaticallyOption: NSNumber(value: true),
        NSInferMappingModelAutomaticallyOption: NSNumber(value: true)
    ]
    let _ = try persistentStoreCoordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: storeURL, options: options)
} catch {
    try? FileManager.default.removeItem(at: storeURL) //Erase old sqlite
    // Make new persistent store for future saves
    let _ = try? persistentStoreCoordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: storeURL, options: nil)
}

Launch this with data from a previous version. A breakpoint in the catch block never triggers so the migration must have worked.

Since I'm in development, what happens if I run a different branch that doesn't have the new model? I assume the catch block is going to trigger—but it doesn't!

Why doesn't it trigger? Does Core Data essentially ignore the new entity property, so all is well?

I was just surprised ...