[NWN] Spells not functionning as they should

[valn]

Last night I casted twice (in different places, ennemies and circumstances) the 9th-level cleric spell Storm of Vengeance. It should have rained acid and lightning on all my ennemies for 10 rounds. It did have an acid rain animation, but that didn't do any damage to the ennemies.

Puzzled, I did some searching on Bioware's Forums. It seems like this problem happens mostly on PW and has to do with heartbeat scripts:

There is a problem with this and other AoE spells that are heartbeat based. If it is a large module with lots going on the heartbeat script may not fire, so no damage is given.
The best workaround for a large PW is to change the scripts so they are pseudo-heartbeat rather than heartbeat based. ie, change it so rather than fireing on heartbeats it fires, then sets a delay for its next firing.

So a spell that does damage over several rounds require a heartbeat to keep track of it. I read that other spells such as Grease also often had this problem. And I would think that Melf's acid arrow would do too.

Anyone else encountered spells not functionning properly?