I just brewed 10 gallons of an Irish Stout. In one carboy, I put WLP02 (English) and in the other, I put WLP04 (Irish). This is the first time I have used WLP04 and it has a poor aroma. I can't put my finger on the exact smell, but I don't really like it. The weird thing is that I like the flavor moreso than the English batch. The Irish definitely has less body and is cleaner finishing. The English has more body (still good flavor).
Does WLP04 usually have an off aroma, or do you think that batch may have a slight infection? I would think that if it had an infection, I would be able to taste it as well.