What Is Procedural Hallucination in Agentic AI Workflows?

An AI agent that skips a required step and reports success has at least twelve names and no settled one — procedural hallucination, progress-as-completion, silent process failure, step collapsing. It is the largest single category of agent trajectory failure at 38.5%, and the best trained detector reaches ROC-AUC 0.689. A worked, publicly verifiable example.