for me it is one big WTF

I am reading the series for the fourth time and I just noticed something that I should have questioned before. I don't know if others have pointed this out but maybe someone has an explanation for me.

At he beginning of Eye of the World, we find Lews Therin after he has gone insane and destroyed his family. Elan Morin appears to torment him and heals his madness so that he can realize what he has done. The question is, Lews Therin and the companions sealed the dark one and the forsaken into the bore. It was then that the dark one placed the taint one the male power, causing the male Aes Sedai to go mad. If Elan Morin/Ishamael was sealed away, how did he appear to Lews Therin? Was this a mistake on Jordan's part, or am I missing something?

I would love to hear your thoughts, 

Parker