It came from the British not US Intel so if anyone is not telling the truth it was the Brits not the US who had flawed intel.
We share Intel with 80 plus countries and they lay them out like a jigsaw puzzle and some pieces look like they fit but when you get to the end of the puzzle they don't go where you thought they would go but the picture of the puzzle ends up looking like you thought when you only had half the puzzle done.
Intel is a best educated guess and not 100% fact !
this particular piece of intel was never anyone's "best educated guess," but it was passed on to the american public and the congress as if it were.