The "duplicate_subscription" value under the "OPT_OUT_SOURCE" refers to the subscription attempts to a campaign that the user was already subscribed to at the time of the attempt. These duplicate subscription records get created as opted-out directly without an activated_at date/time because we keep the original/first subscription record active (as long as there are no opt-out attempts).
Answer
The "duplicate_subscription" value under the "OPT_OUT_SOURCE" refers to the subscription attempts to a campaign that the user was already subscribed to at the time of the attempt. These duplicate subscription records get created as opted-out directly without an activated_at date/time because we keep the original/first subscription record active (as long as there are no opt-out attempts).
For the duplicate subscriptions records with Activated_at values, there were other subscriptions made to the same campaign by these profiles at the same date/time stamps which is a very rare scenario. Other than these, all the duplicate subscriptions were created without an activated_at value.
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Question::Product How-To / Training
Internal Information