Well its hard to pinpoit the problem I don't think its pub or gfx related because it happens on chars with nothing and maps with on 1 npc type spawn.
It's very much like I said, sometimes after killing an npc everything goes invis, what triggers it is an npc kill, that's the only thing I know for sure.
Just today this happened: start client, go to map, kill npc, everything goes invis.
Close client, set it to run as win vista service pack 2, launch, same map, kill npc. everything good.
Close client, set back to run as win 10 normally, launch, same map, kill npc. everything good...
It's very odd..
And @callum I think this started when u fixed the Eoserv rev that had ranged line aoe... idk if u remember. *edited I tested the game with the orignal eoserv 0.7.0 and it worked fine, so your rev is causing the problem