What is Citation card drift?

Citation card drift is the shift in citation-card composition — publisher badge, favicon rendering, page-title truncation, timestamp chip, thumbnail, or card position — on an anchor-slot-winning chunk across sessions, even when the underlying page has not been edited. Mid-2026 cohort: roughly 24% of citation cards on anchor-slot-winning chunks shift within a rolling 8-week window across the general-purpose engines. Four observable causes require different fixes: publisher-registry re-scoring (the engine re-runs the publisher-badge resolver against an updated registry and previously resolved brand strings collapse to bare domains, or vice versa), UI redesign (the engine ships a card-format revision that changes title budgets, adds or removes timestamp chips, or introduces or retires thumbnail slots), card-position demotion under competitor sharpening (a competitor's publisher-authority strengthens and pulls card position), and thumbnail slot substitution (the engine picks a different image from the cited page as the thumbnail — often a newer content image or a replaced og:image tag). The card-drift audit captures citation-card identity weekly per priority sub-query per engine, computes drift rate on a rolling 4-week window, and diagnoses the cause before scoping the fix — card-surface losses attributed to the wrong cause produce zero lift and burn editorial bandwidth.