Why are phase-gate Milestones problematic?

Phase-gate milestones are problematic because they often use documentation as a proxy for solution

progress. This approach assumes that completing certain documents or passing through predefined

gates accurately reflects the progress of the solution. However, in Agile methodologies, working

software is the primary measure of progress. Relying on documentation can lead to a false sense of

security, where teams believe they are on track based on completed paperwork rather than actual

working software. This can delay the discovery of issues and hinder the ability to make necessary

adjustments in a timely manner.

SAFe Scrum Master Reference

SAFe Principles: valuing working software over comprehensive documentation

SAFe 5.0 framework: the drawbacks of phase-gate milestones and the emphasis on iterative progress

with working solutions