When is a session or contact bucketed under “Other campaigns” in HubSpot?

Other campaigns in HubSpot captures visits from contacts who arrive via tracking URLs that are associated with HubSpot campaigns but cannot be attributed to a specific standard source. This ensures that marketing efforts using unique tracked links are recognized, even when the original traffic source is ambiguous. It allows tracking of email links, paid ads, or custom campaigns without misclassifying them as organic, social, or direct traffic. HubSpot automatically buckets these interactions under this category to maintain accurate campaign reporting.