A period of 0.1 with Nose-Hoover is too short. You should use at least tau-t=1 ps.
And I would suggest to use tau-p=5 ps. Having the box change on a 1 ps time scale with semi-isotropic could cause issues.
PS: I think your nsttcouple should have been automatically set to 5, not to 100. So this would mean you now increased, not decreased, it to 10.