character randomly become invisible

[Ayame]

I don't know if it's just me but randomly when I zone one of my character would go invisible. On one of my charater screen I can see both character on the other screen I can only see the main character even the servo command doesn't respond to the invisible character unless I use the invisible charater. I'am running both character from the same computer. I saw a thread about invisible character
but my issue doesn't involve npc only my characters and I'm on a 780 gtx video card.

this is on old school server