Yep. Poblanos can be sneaky, varying in heat from batch to batch. Not much to do that's worth doing. Same as the perennial question about to much salt.
Well, there are some things you can try, if you think the salvage job is worth it. One is to add fat, meaning mostly yogurt, sour cream and such, those being things that can usually reasonably be added to soups. The hot part is soluble in fat, which those things have, which is why you drink milk, not water, when you get into overly hot peppers. (But don't use non-fat or low fat, of course). At the same time, adding sugar and/or acid is said to help. It's also said that adding potato or pasta helps, but I suspect the real reason is that you generally have to add water, too, and that's what dilutes the heat.
"Kitchen duty is awarded only to those of manifest excellence..." - The Master, Dogen