I noticed something similar on a project I was on. I was given the task to supervise external contractors but given no authority to tell them how to do things. I basically had to convince them with arguments. Well predictably it's pretty hard to convince somebody that they are wrong but it's nearly impossible if it will also cut the project time in half which means it will cut the money for them in half. So naturally there was quickly a quarrel because they wanted to keep doing things badly and it was my assigned job to prevent exactly that. I was eventually overruled by my own management though because I can't compete with several external project managers whose entire job it is to talk their way into more money. They were willing to outright lie and there was no incentive to believe me vs. believing the supposed expert contractors.