It's a mistake. If it was done by an auto-correct mechanism, would we still say "maybe don't sell your word processor to the army if you can't vouch for its auto-correct system!!!"? Besides, "taking notes" can literally be listing targets, and "getting from A to B" can be the road to killing them.

How intelligent and autonomous does a murderbot have to become before you stop absolving its creator and seller from any responsibility?

If the US military purchased camera guided smart munitions with a miscalibrated camera, such that it ignored adult targets and instead specifically targeted children, would that also be a simple mistake per your argument?