# Contacts in Sequences receiving duplicate emails

**URL:** <https://community.hubspot.com/t/contacts-in-sequences-receiving-duplicate-emails/147466>\
**Category:** Email Deliverability\
**Tags:** sequences\
**Created:** [March 19, 2026, 4:16pm UTC](https://community.hubspot.com/t/contacts-in-sequences-receiving-duplicate-emails/147466 "2026-03-19T16:16:12Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Sabs](https://avatars.discourse-cdn.com/v4/letter/s/8797f3/32.png) [@Sabs](https://community.hubspot.com/u/Sabs)\
**Post date:** [March 19, 2026, 4:16pm UTC](https://community.hubspot.com/t/contacts-in-sequences-receiving-duplicate-emails/147466/1 "2026-03-19T16:16:12Z")

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Hi, All:

Quick question - we recently set up a sequence where at least (2) contacts received the email twice. This was surprising since these contacts only had one instance on the list AND HubSpot typically prevents adding the same contact to a given sequence. Thoughts on how this error may have occurred? TIA!

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**Author:** ![karstenkoehler](https://d10pqhm3lwygmk.cloudfront.net/user_avatar/community.hubspot.com/karstenkoehler/32/68554_2.png) [@karstenkoehler](https://community.hubspot.com/u/karstenkoehler)\
**Post date:** [March 19, 2026, 4:19pm UTC](https://community.hubspot.com/t/contacts-in-sequences-receiving-duplicate-emails/147466/2 "2026-03-19T16:19:29Z")

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Hi @Sabs,

Without the ability to poke around and investigate in your portal, this is hard to say. You would have to share so much context here that you’d probably violate the personal rights of the affected contacts. I’d recommend reaching out to HubSpot support in-app via chat or email.

My hypothesis:

- Contacts have multiple email addresses and distinct contact records, were potentially merged later on
- Contacts were accidentally enrolled in sequence multiple times
- Contacts were enrolled in identical sequences after another

Best regards

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**Author:** ![Sabs](https://avatars.discourse-cdn.com/v4/letter/s/8797f3/32.png) [@Sabs](https://community.hubspot.com/u/Sabs)\
**Post date:** [March 19, 2026, 4:33pm UTC](https://community.hubspot.com/t/contacts-in-sequences-receiving-duplicate-emails/147466/3 "2026-03-19T16:33:27Z")

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Thanks for this, Karsten! My understanding is you can’t add a single contact to the same sequence more than once. Is that not the case? In other instances, I did receive an error that a contact had already been enrolled and could therefore not be added again. Does the system automatically merge duplicate instances of a given email? Appreciate you weighing in!

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**Author:** ![karstenkoehler](https://d10pqhm3lwygmk.cloudfront.net/user_avatar/community.hubspot.com/karstenkoehler/32/68554_2.png) [@karstenkoehler](https://community.hubspot.com/u/karstenkoehler)\
**Post date:** [March 19, 2026, 4:36pm UTC](https://community.hubspot.com/t/contacts-in-sequences-receiving-duplicate-emails/147466/4 "2026-03-19T16:36:14Z")

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@Sabs merging a contact who’s enrolled in a sequence shouldn’t work, correct, such as re-enrolling a contact into the same sequence. HubSpot can behave unexpectedly sometimes so I wouldn’t rule out buggy behavior in any of these areas.

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**Author:** ![Sabs](https://avatars.discourse-cdn.com/v4/letter/s/8797f3/32.png) [@Sabs](https://community.hubspot.com/u/Sabs)\
**Post date:** [March 19, 2026, 4:42pm UTC](https://community.hubspot.com/t/contacts-in-sequences-receiving-duplicate-emails/147466/5 "2026-03-19T16:42:09Z")

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Thanks, buggy behavior was my diagnosis as well!