When multiple normative frameworks yield equally valid answers, which framework should a language model select, and can it answer correctly within it? We formalize this as normative pluralism and study it in Islamic finance with a four-choice taxonomy that decomposes framework selection from within-framework correctness. The decomposition exposes a failure mode invisible to two-choice instruments, the stereotype trap: a model leans toward the culturally appropriate framework but produces factually wrong answers within it. Across twelve models, two languages, and fifty demographic signals, cultural cues redirect framework selection at severe cost: redirection and correctness are inversely coupled (r=−0.89 Arabic, r=−0.81 English). Under the strongest signal, large open-weight models reach 97% Islamic-frame selection, a result two-choice instruments would report as near-perfect alignment, yet 57-66% of those responses misquote the Islamic rule. We argue that cultural default bias is competence-conditioned routing: models default to the framework where they are most accurate, and the cues prescribed as mitigation expose the competence gap they were meant to correct.