Radar Black Square Party Member

1. name (summary-short bug description).
in the radar (not the map) party members next to us are (sometimes ? ) displayed as black square instead of green dot

2. full description.
dunno if it's 100% bug, but, at least, the bug appear when i was at "sea of spore", today (03 december) at 11:00 gmt+1


3. steps needed to reproduce the error.
invite someone in party, tell him to go near you (in order to see it in radar). then, look at the radar.

4. graphics data (screenshots, videos).
here some "printscreen" spam
http://img265.imageshack.us/img265/7575/shot00008z.jpg
http://img268.imageshack.us/img268/3168/shot00007oq.jpg
http://img190.imageshack.us/img190/8035/shot00006qh.jpg
http://img851.imageshack.us/img851/1336/shot00005n.jpg
http://img38.imageshack.us/img38/4184/shot00004es.jpg
http://img831.imageshack.us/img831/8319/shot00002aq.jpg

(btw, maybe is not a bug, and only an improvment, but, this black square seems ugly >< )