analyze_glitches "ValueError: minvalue must be less than or equal to maxvalue"

See https://ldas-jobs.ligo-wa.caltech.edu/~lockloss/events/1239/256056/log:

Traceback (most recent call last):
  File "build/bdist.linux-x86_64/egg/locklost/analyze.py", line 48, in analyze_event
    
  File "build/bdist.linux-x86_64/egg/locklost/plugins/glitch.py", line 571, in analyze_glitches
    plot_snr_eventmap(event, triggers, sample_rate, zoom)
  File "build/bdist.linux-x86_64/egg/locklost/plugins/glitch.py", line 524, in plot_snr_eventmap
    orientation="vertical"
  File "/usr/lib64/python2.7/site-packages/matplotlib/colorbar.py", line 298, in __init__
    self.draw_all()
  File "/usr/lib64/python2.7/site-packages/matplotlib/colorbar.py", line 323, in draw_all
    self._config_axes(X, Y)
  File "/usr/lib64/python2.7/site-packages/matplotlib/colorbar.py", line 409, in _config_axes
    self.update_ticks()
  File "/usr/lib64/python2.7/site-packages/matplotlib/colorbar.py", line 345, in update_ticks
    ticks, ticklabels, offset_string = self._ticker()
  File "/usr/lib64/python2.7/site-packages/matplotlib/colorbar.py", line 560, in _ticker
    ticks = self._locate(b)
  File "/usr/lib64/python2.7/site-packages/matplotlib/colorbar.py", line 790, in _locate
    b = self.norm(self._boundaries, clip=False).filled()
  File "/usr/lib64/python2.7/site-packages/matplotlib/colors.py", line 948, in __call__
    raise ValueError("minvalue must be less than or equal to maxvalue")
ValueError: minvalue must be less than or equal to maxvalue