Poor Sprint planning process
Poor Sprint planning process, e.g. workload fully matches capacity, no buffer preserved or/and day offs are not taken into account
Discovered by combination of metrics:
Velocity: Committed vs. Completed, when team does not meet commitments leaving sprint backlog in not completed state by the end of iteration
Average Velocity, when team's productivity keeps on the same level without any signs of growth or degradations are observed over time
Sprint Plan Change, high percentage of items being added or removed during active iteration