If the email threading for the particular contact is enabled, then that contact will receive all sequence emails that are a part of the thread and not as an individual conversation. It is helpful in a way that the contact has all the previous conversations at a place and is able to see all of them together.
Enable / Disable threading for a Sequence
- Go to More >> Sequences
- Click on the sequence name
- Click on the Settings tab
- Click on Enable Threading to enable or you can even disable it based on your preference.
- Hit on Update