S-Curve histogram shape is wrong

Traceback:
File "/home/michael/git/bdaq53/bdaq53/analysis/analysis_utils.py", line 752, in fit_scurves_multithread
    n_injections=n_injections)
  File "/home/michael/git/bdaq53/bdaq53/analysis/analysis_utils.py", line 679, in get_noise
    mu1 = y[x < mu].sum()
IndexError: boolean index did not match indexed array along dimension 0; dimension is 79 but corresponding boolean dimension is 80

This error stops the analysis. I would like to see the S-Curves even without the fit results, just to know in wich direction i should tweak my parameters next... This error should be handled, maybe give a warning but it shuold not stop the analysis completely.