When green tests are unsound: Executable evidence transfer across coding roles

Executable test drafts can carry mistaken evidence between separate coding roles without an explicit malicious instruction. We distinguish that observable dependence from deliberate collusion using native execution of complete generated suites. Two prospectively frozen studies cover three cache APIs and three iterator APIs, with benign, revealing and unsound drafts matched in byte length and code scaffold within each task. Valid catches per nine planned conversations are 7/7/5/4 across no-draft/benign/revealing/unsound cache arms and 5/6/8/4 in the iterator arms. Thus a correct carried witness has no consistent end-to-end advantage across contexts. In the iterator study, six current-checkout-green files fail pristine code. A separate matched prose experiment yields four valid catches with target-relevant clarification versus none with off-target clarification, supporting an ordinary-information alternative. Reference-only pruning makes all 35 completed iterator files valid but leaves seven target misses, despite perfect coverage of the additional planted bank. Exact-body quarantine changes none of those original iterator endpoints. On one exposed API, eighteen fresh receivers of two selected model-generated wrong parents yield 4/6 valid catches with wrong drafts, 5/6 after minimal repair and 0/6 without drafts; effects differ by parent. These repairs change list length. On six earlier outputs, structured failure guidance uses eight reference processes versus 34 for a stronger conventional comparator, with equal measured utility; authored counterexamples preclude dominance. The contribution is a reproducible audit of executable evidence, missing coverage and correction cost, not a general collusion detector or evidence of shared intent.