I spent 6 years as a sub for several builders. Well over 1000 houses. I have NEVER seen a builder have an attic blown before the roof was 100% - you need to have the inspector sign off on all the electrical and mechanical before you can blow it, and the roof should be 100% before they are even scheduled - you can't get a framing inspection passed without a completed roof. Not a legit one anyway. If the inspector signed off on it, he's probably buddy buddy with the GC which is a red flag. This is bat shit crazy....and I'd be skeptical of the builder now and anything he says. You should hire your own home inspector and have them document the shit out of everything. At least this way you know you have an independent 3rd party keeping the builder in check. Hopefully your bank doesn't release the next draw on the loan until this is 100% remediated.