Quick landing tests routinely 'win' for the wrong reasons: a paid‑social push that showed a 20% uplift only because a cached variant served repeatedly, or an influencer referral that inflated signups with bot-driven events. In this 15‑minute episode Gustavo (instrumentation) and Michelle (brand/UX) walk through a vivid micro‑case, then deliver an action-first playbook: three non‑tech checks any marketer can run, concise definitions of common technical traps (e.g., deduped events = removing double‑counted conversions; cache‑aware tagging = marking variant responses so caches don't hide differences), and one concrete sample‑size heuristic: aim for at least 250 unique visitors per variant or 30+ conversions per variant—otherwise label the result inconclusive. The show includes a 60–90s narrated walkthrough of the downloadable one‑page bias checklist and a prefilled QA script with examples. Listener challenge: run the three checks in your next 72‑hour test and grab the assets to report back. Download the bias checklist and sample QA script with prefilled examples to get started.