I noticed about a month ago that every post I saw (whether I posted it or not) shows this icon. I'm getting used to it but would like to resolve it if it is an issue on just my end (I wouldn't know where to begin with something like this though).
My default post setting for all the smileys/icons at the bottom of the post is "No Icon."
For those who cannot see the attachment, when you reply to a thread, you have the option of all the little smileys/icons at the bottom. What is showing for every post for me is the "sheet icon" (first on the left, above the original smiley face).
It appears to be the location of the message title for each topic of discussion. Title in the first post, blank thereafter. Same icon that is after the envelope on the main forum title page.
... but my default is set as "No Icon" and I check every time that "No Icon" is selected, and it still brings this up. But that's only half the problem, every post I view in a forum, written by me our anyone, shows that icon. I'll post a screen shot: