What I do find frustrating is when they only concern themselves "happy path", and developers don't have the authority to fill in the gaps. It creates a waterfall-like experience where you are often stuck waiting to hear back from product/design to make a decision because they didn't consider a scenario where the user might submit a form with an incorrect field or some other seemingly obvious path.
Another bad practice is product people who assume screenshots or Figma files are technical requirements; not realizing these only give you clues as to how something will look, not how something will work, so flows and business logic go under-examined by product, which can lead to more "let's hold off on that, let me think about it" after telling you to start something ASAP.