Technical SEO recovery after a WordPress redesign

An edtech publisher relaunched on a new WordPress theme built by another company. Traffic looked stable for two weeks, then organic impressions fell 41% over 60 days. Search Console showed exploding "Crawled, currently not indexed" counts, soft 404s on legacy course URLs, and hreflang errors on a small Hindi subsite.

Audit findings: (1) two SEO plugins active, Yoast and Rank Math, producing duplicate meta and conflicting canonical tags; (2) sitemap index returned 404 because nginx rewrite rules omitted wp-sitemap.xml after a permalink flush; (3) trailing-slash inconsistency, half the internal links used /path vs /path/; (4) 1,800 orphan pages from a custom post type never linked in nav or HTML sitemaps; (5) schema markup referenced Organization @id that changed on every deploy.

Problems during fix: marketing had already printed QR codes to bare slugs that we needed to 301, not 410; Hindi subsite used subdirectory /hi/ but hreflang pointed to a subdomain that did not exist; removing Yoast broke editor workflow mid-sprint, we migrated settings export instead of cold-turkey uninstall.

Remediation sequence: single SEO plugin policy (Rank Math); nginx + WordPress rewrite parity test suite; 301 map from Screaming Frog + GSC export, 2,340 rules loaded via Redirection plugin with regex QA on staging; orphan CPT pages woven into topic hubs and XML sitemap; stable @id in schema via wp_options constant.

Monitoring: weekly GSC coverage report; log file analysis for Googlebot hit rate on /wp-json/ and faceted search URLs (blocked via robots.txt where appropriate); Core Web Vitals regression tied to template changes.

Outcome: impressions recovered to 97% of pre-launch baseline by week 16; "Crawled, not indexed" ratio cut by 68%; rich result eligibility restored for course schema on 120 URLs. Client referenced as a national test-prep publisher, name not disclosed.