RMG unit test failure on Summit

[scallag]

The unit test test_rmg fails on Summit:

ERROR: test_rmg (test_rmg.TestRMG)

Traceback (most recent call last):
File "/gpfs/alpine/geo112/proj-shared/CyberShake/software/bbp/bbp-19.8.0-python3/bbp/tests/test_rmg.py", line 67, in test_rmg
rmg.run()
File "/gpfs/alpine/proj-shared/geo112/CyberShake/software/bbp/bbp-19.8.0-python3/bbp/comps/song_rmg_single_seg.py", line 1295, in run
self.gen_rup()
File "/gpfs/alpine/proj-shared/geo112/CyberShake/software/bbp/bbp-19.8.0-python3/bbp/comps/song_rmg_single_seg.py", line 1005, in gen_rup
self.gen_dist()
File "/gpfs/alpine/proj-shared/geo112/CyberShake/software/bbp/bbp-19.8.0-python3/bbp/comps/song_rmg_single_seg.py", line 801, in gen_dist
L = np.linalg.cholesky(cm)
File "/sw/summit/python/3.6/anaconda3/5.3.0/lib/python3.6/site-packages/numpy/linalg/linalg.py", line 614, in cholesky
r = gufunc(a, signature=signature, extobj=extobj)
File "/sw/summit/python/3.6/anaconda3/5.3.0/lib/python3.6/site-packages/numpy/linalg/linalg.py", line 92, in _raise_linalgerror_nonposdef
raise LinAlgError("Matrix is not positive definite")
numpy.linalg.linalg.LinAlgError: Matrix is not positive definite

My Summit environment is:
[[email protected] tests]$ module list

Currently Loaded Modules:

1. hsi/5.0.2.p5 6) python/3.6.6-anaconda3-5.3.0
2. xalt/1.1.4 7) gcc/6.4.0
3. lsf-tools/2.0 8) spectrum-mpi/10.3.0.1-20190611
4. DefApps 9) fftw/3.3.8
5. cuda/10.1.168