Rebecca Lewis points out when optimized locking fails:
SQL Server 2025 introduces a feature called Optimized Locking, designed to reduce blocking across read–modify workloads. In many environments it helps, but certain mixed workloads experience longer lock waits, stalled S → U → X transitions, and even occasional threadpool saturation.
My inner 12-year-old has already made about a half-dozen plays on the phrase “When optimized locking SUX.”