Tell me about a disagreement you kept to yourself longer than you should have. What happened, and what made you finally raise it?

Asking for the failure case ("too late") lowers the incentive to perform and surfaces how the candidate actually handles conflict cost, not how they think conflict should be handled in theory.

• What did staying quiet cost the team or the project?
• What signal would make you speak up a week earlier today?
• How did the other person react when you finally raised it?

An honest account with a real cost attached, insight into their own threshold for speaking up, and evidence the threshold has moved.

Claims to always speak up immediately, frames silence as purely the environment's fault, or the "disagreement" turns out to be trivial.