If the PM was also an ex-developer and has both product management and development skills this happens a lot less. When the PM knows the Engineering and complexity and code debt cost of shipping a feature then they can self-triage with that additional information and choose not to send it to the developers or to consult with dev and scale it back to something more managable.

Its these professional PM's that have done nothing else other than project mangement or PMP that don't have an understanding of the long term dev. cost of features that cause these systemic issues.