WordPress Block Theme Changes Not Taking Effect? FSE Development Troubleshooting Guide
Encountered these five issues repeatedly while developing WordPress Block Themes for clients. Each one took significant debugging time. This guide covers the root causes and provides ready-to-use solutions.
TL;DR
Five issues ranked by frequency: file changes not applying (database cache overrides files), block nesting errors (unclosed comments), child theme content not rendering (missing post-content block), SVG icons disappearing (WP_Filesystem polluted by plugins), and WP-CLI mail failures (SMTP plugins don't hook in CLI). Each scenario includes copy-paste diagnostic commands.