A post was written by staff member. The post is a response to another post (by non-staff member) and has the “in response to X” symbol at the top right corner. (As it happens, the message is the one right above it.) Clicking the symbol opens up the message again on top of the message (showing the message to which the post is a reply to).
The post by staff member had staff color added. The color applied (bug!) to the replied message as well.