As I was testing glitchs/bugs this one came up, I never use Xavi so I always have it off, however when you type /-Xavi it doesn't "save" as a turned off power properly and sometimes can be bugged, which means Xavi will show for other users, and show as whatever avatar you are actually using.
Turning Xavi off/on in your list of powers does not properly save as well, however it seems to work more so then typing /-Xavi
*2. Add a avatar/animated gif
*4. Sign in/out and refresh
*5. Type in chat/pc