Scenario:

1. There is a Journey where input flow is 1000 contacts.
2. There are 2 branches: SMS and Email.
3. Now for SMS, there is no deduplication on Mobile number, so SMS is sent to all 1000 contacts (one person probably receiving SMS more than once) -> Require SMS deduplication
4. Email has deduplication feature and so Email is sent only to 800, filtering 200 contacts due to deduplication.
5. After Email, there is a component to create follow up Phone Call activity.
6. There is no deduplication post Email, so Phone call activity will be created for all 1000 contacts i.e. for those 200 filtered contacts as well, generating unwanted activities for CRM and users to handle -> Require Deduplication option (Yes or No) for corresponding branch