Accessing obj.evidences on a session-expired ORM object (mutation endpoints
do commit+refresh without joinload) triggers a lazy query that fails or
returns stale data. Use obj.__dict__.get('evidences') instead — SQLAlchemy
stores joinloaded relationships in __dict__; absent means not loaded.
Mutation endpoints (submit-red, submit-blue, etc.) return empty evidence
lists, which is fine: the frontend invalidates and refetches GET /tests/{id},
which uses joinedload and correctly populates red_evidences / blue_evidences.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>