World of Warcraft NPC will not see what is happening when it is closed.

I often encounter this situation, not only NPC, but also mine. I think this situation is generally a network problem. When you are far away from NPC, the picture is the big environment, and the specific details are not brushed out. When you get close, because you need to brush out specific particle details, you will occupy a large part of the network, and then you will adjust the details of the picture again, that is, NPC will disappear first, then become clearer, and then brush out NPC after the surrounding environment is clear.