The sanitize_field() fallthrough for JSON fields starting with '['
called sanitize_text_field() which escaped quotes and brackets,
breaking json_decode() on read. This caused subreddits, topic
exclusions, and enabled sources to always read back as empty arrays.
Now properly decodes, sanitizes each item, and re-encodes as clean
JSON for all three input paths: PHP array, JSON string, or CSV.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
6cf8ff62fc