Example: ```python def setup_class(cls): set_datadir(tmp_dir.name) cls.sched_kwargs = { "times": np.linspace(0, 80e-6, 21), "qubit": "q0", } cls.sched = ts.echo_sched(**cls.sched_kwargs) cls.sched = qcompile(cls.sched, DEVICE_CFG) ``` This causes illegal wait times to occur in the backend, because the wait times get set to values that are too small for the first few points (due to the `np.linspace(0, 80e-6, 21)`). This can be solved by replacing the 0 by a larger value. In the old pulsar backend this silently fails, but in the new backend an exception is raised instead (so this is blocking !81).