X_JOB_SIM_NONDETERMINISTIC
Means
one simulateJobs seed produced two different traces
Typical cause
a job body reads something the simulation does not own — the wall clock, real I/O, state left by an earlier run — so a seed cannot replay
Fix
x test job --seed <n> --filter <the test file> — the first differing event is printed; read the clock and ids through the frozen seams