Two portals, one house, two records. Merging them is easy. Merging the wrong two is invisible and expensive. A practical look at blocking, match scoring, survivorship rules and the time axis most listing pipelines get wrong.
Three CRM records, one person, and nothing in the logs to explain it. A practical walkthrough of what actually breaks when you unify Shopify, Stripe, CRM and support data: guest-checkout identity, duplicate and out-of-order webhooks, revenue that never ties to payouts, deletion requests that miss half your copies, and reverse ETL write loops. Organized by failure family, with schema and handler patterns you can apply directly.