https://github.com/Qiskit/qiskit-experiments/blob/049436a3d184adb51bb559316483cd44f1e2c925/qiskit_experiments/framework/experiment_data.py#L1339

Here; if you hit this condition the experiment data is not saved, but the function returns as if it had saved. In the context of, for example launching a bunch of experiments from a loop, this could cause a user to lose a lot of data. (or am I missing something here?)