hashcat stops after about 37 minutes

[patpro]

I'm running Ubuntu:

Code:

Linux nutcracker 4.4.0-87-generic #110-Ubuntu SMP Tue Jul 18 12:55:35 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

with those nvidia related pkg:

Code:

nvidia-375/xenial-updates,xenial-security,now 375.66-0ubuntu0.16.04.1 amd64 [installed,automatic]
nvidia-opencl-dev/xenial,now 7.5.18-0ubuntu1 amd64 [installed]
nvidia-opencl-icd-375/xenial-updates,xenial-security,now 375.66-0ubuntu0.16.04.1 amd64 [installed,automatic]
nvidia-prime/xenial,now 0.8.2 amd64 [installed,automatic]
nvidia-settings/xenial,now 361.42-0ubuntu1 amd64 [installed,automatic]

I can provide sample input files upon request (private message?)