I need a seasoned Moodle core architect to trace and resolve a series of functionality bugs that are affecting day-to-day use on my live site. The symptoms range from features silently failing to occasional fatal errors when certain activities are saved, so this is not a simple plugin tweak—I’m looking for deep, core-level diagnostics and clean, maintainable patches. Your task is to identify the root causes in core code, implement fixes, and confirm that every affected workflow runs smoothly again without introducing regressions elsewhere. You may have to step through the plugin architecture, examine the database schema, and validate calls to Moodle’s web-service APIs to be sure the problem is fully solved. Deliverables • A concise report outlining the source of each bug and the code paths touched • Tested patches or pull requests ready to merge into core (with upgrade script if the DB schema changes) • Verification notes or automated tests proving the issues no longer occur on a vanilla install and on my production clone I’ll provide SSH access to a staging clone, issue descriptions, and any logs already gathered. Please be comfortable working against Git, following Moodle coding guidelines, and documenting changes so future upgrades remain straightforward.