Wrong forum, m'dear. You want the
Site Feedback forum.
The Q&A is designed for people needing help traversing the site, have questions about the TOS, if an item exists and if so what it's called, etc.
The chest plate isn't really a glitch, but since the Feedback forum has become a place for constant B&M-ing, you can try posting in the
Avatar Item Glitch Report Thread
Bear in mind it was a sponsorship item, so that might be how the sponsor wanted it to be designed