Like most things in EQ, blind is not guaranteed to work. If you are moving then blind has a much reduced chance to work. Also on Live servers, if you deaggro the NPC while blind it will bug out and run into a straight line for 10 or whatever minutes, continuing long after the spell had worn off and into a zone wall. On Live stuff also gets stuck in low aggro flee mode even after hate lists are wiped, so they may have broken flee behavior on NPCs without active hate lists at some point. I'm not sure how it behaved after hate wipes on AK. The spell's behavior on Live otherwise matches old EQ comments and logs however, as far as I can tell.