User blog comment:DaNASCAT/Technical Update: November 21, 2016/@comment-31248264-20161122002820/@comment-126761-20161122150546

A fix for this is now live! Altering thread info should no longer remove other attributes (highlight status, topics, titles). You may need to reapply info that was incorrectly removed, but doing so should no longer cause problems.

Apologies for the confusing (and annoying) behaviour.