i have been playing on Nero for a week or two now and i can confirm this is still an issue also to add more info your suggestion of F3+A dose not work that was my first idea and teleporting out and back in dose not work either it seems to be a desync atleast for me anyways a complete relog is necessary to correct the issue also note only seems to be AoA mobs that i desync with
There are Ghosts and Shades in Nevermine/AoA, if you look at them directly they turn invisible and can kill you. (Sì I know it's September but it happened in August too.)
For anyone having this issue. Check if your particle effects setting is turned all the way up. Some mobs are only seen when you have them turned to ALL. There use to be a similar issue with infernal mobs, where partial and minimal settings would cause players to not see some mobs.
"Also seems to be only AOA mobs..." That is useful, but I've never experienced AOA mobs being invisible, and I always have settings to minimal (I don't want to get into the whole really long explaining, so to shorten it: My computer has heat problems, so )
I remember similar issue on infinity, but invisible mobs weren't doing any damage to players there (I standed in a płace with like 30 crimson knights and I was thinking that someone killed them, but when I relogged I almost died).