Baldur's Gate : The Sword Coast Chronicles : NWN2 Persistent World

Clerics can spontaneously cast either cure/inflict wounds spells, basically convert a memorized spell splot into the cure/inflict spell. Furthermore, inflict wounds spells can be used to heal undead and healing spells be used to damage undead.

Source: BG:TSCC Wiki: Spontaneous Casting

So to do this as far as I'm aware, one needs to use the quick cast feature and then click on the spontaneously convert spell button.

Here is the thing, whenever I click the spell conversion button it switches, so that part is working. However, I have not been able to use spontaneous casting to use cure/inflict wounds with undead, inflict wounds especially on my own animated ones, so either I'm not doing it correctly or its not working as it should. Whevener I try, I click on the the spell conversion, then the cure/inflict spell as appropriate, then try to click on the undead I want to cast it one, but it won't let me.

Can someone shed some light on this?

It's bugged. I flagged this several months ago but I considered it a low priority fix for the Dev team given how few players actually bother to heal their own undead.

It has something to do with how the new summon system uses a 'Domination' mechanic and that the game will not let you target such creatures with Inflict Wounds spells (kinda like how it won't let you target neutral NPCs with them). The bug also affects the sorc/wiz spell Negative Energy Ray.

Mass Cause Wounds, cast via spontaneous conversion, do work, although you must target the ground or an enemy near the undead you wish to infuse. Make sure you're Deathwarded when you do this, though, cuz you cannot escape the radius of those spells yourself.

So basically its not working as it should.

Thanks for shedding some light on it, and thank you for the advice