New tickets from email are being associated with old threads and wrong departments. Some threads show content from 4-year-old tickets.

The root cause was partial table imports from previous osTicket instances into ost_form_entry. The object_id values in the imported rows collided with existing ticket IDs, causing the system to attach old form entries to new tickets. Never import individual tables across installs -- always perform a full database migration or start fresh. If AUTO_INCREMENT collision is suspected (MySQL < 5.7.5), reset it with: ALTER TABLE table_name AUTO_INCREMENT = ; and upgrade to MySQL 5.7.6+ or 8.0+ for persistent counter support.