Post: #4

try using LOCAL.Duration=<R10,20> to check if the spell set the timer value randomly to each wall item, if you use an fixed value like LOCAL.Duration=10 it will set TIMER=10 on all items

are you using MAGICF_OSIFORMULAS on sphere.ini? As you described the poisoning problem, maybe the fault is not on the poisoning spell but on how you're healing the poisong (which is not removing the poison effect correctly). So after you cast poison and cure this poison for the 1st time, try type .xedit and click on the player to check if the poison memory got removed correctly