This appears computer specific... doing same test on a different CPU, all is fine 😬 This is a little concerning...

Library implementation bug?

reinstalling libopenblas/numpy fixed the problem! sudo apt-get -y autoremove --purge 'libopenblas*' sudo apt-get -y install libopenblas-base pip install --upgrade --force-reinstall numpy thanks to Yaroslav Bulatov for pointing out that numpy could be using different backend versions.

Repeat 100 times on each computer? Is it some work with their solver and np. R random?