It seems like I get this message on the HUD when changing into a different avatar, then changing back to the one I was in previously. It will continue to show up each time you change into something you've already worn during your session. Hope this gets patched soon.
I don't think it's appropriate to have it as a HUD message after using the avatar menu; it's quite redundant, when it already displays the message in the avatar menu. The only use case that I see this HUD popup for, is for clicking on avatar pedestals.