Necro Spells -100 to -200 modifier spells resist frequency.
 

Usually I wouldn't make a bug report about this, but there seems to be an increased frequency for resists on R99 with Necro spells on NPCs.

I've tested this over a grind session in VS area for about 3-4 hours on all mobs with a 60 Necro, however, I have seen things such as Soul Well (-200 resist check), splurt (-100 resist check) and deflux (-200 resist check) get resisted up to 2 times in a row.

I will get some logs of this next time I'm in a grind/farm session, but for now I am making a note of the issue in case other players are experiencing the same issue/variance on spells that should be more or less lure.

If I remember correctly, they put in a static 1% resist chance on all spells, regardless of a resist modifier. It is still possible that two 1% chances happen back to back.

Possibly check your log and check the resist rate on spells verus overall casts? It may be that you're just noticing the silliness that lifetap like spells, a spell often in classic sources referred to as "unresistable" can be resisted 1% of the time by green cons, lol.