SymptomOutput is plausible and internally consistent but wrong in a specific field. Documented instances: a course level returned as Beginner where the canonical page said Basic; a dual duration field where the agent treated an upper bound as a fixed total; a prerequisite check silently absent from a skill.
CauseThe agent paraphrases rather than copying, and infers a single value where a source prints two.
DetectionOnly by diffing against the canonical source. The prerequisite gap surfaced only when the skill was tested against a different input than the one it was built on.
FixInstruct the agent to reopen the page and copy printed labels verbatim rather than normalising them. Preserve every printed value where a source shows more than one. Test each skill against a second, different goal before scheduling it. Do not save a process until the manual version works, or the skill will just repeat the same problem.