White / Black / Messed up screen?

[Bloody]

I used to think it was just me, until other people in my party/guild mentioned it. Sometimes on certain maps (Niff, Seals, Sea Otters...etc) the map starts flashing and the map's ground changes to a different color. June it turned white, July it turns black and I don't remember what was May's color.

Is there another topic about this? A link would help. If not please someone look into it, it gets so annoying. You have to close the client to fix it, and sometimes it just keeps happening over and over after you relog.