Minimizing energy for a system which is in a small cell but has pbc=False can lead to complete breakdown, with atoms moving in all sorts of unphysical ways and energy diverging to negative values. I'm not sure what the right way to deal with this is (my instinct would be for the cell vectors to just be ignored) - might be best to be consistent with what ASE thinks should happen. But it'd be nice if this was detected at least.
Minimizing energy for a system which is in a small cell but has pbc=False can lead to complete breakdown, with atoms moving in all sorts of unphysical ways and energy diverging to negative values. I'm not sure what the right way to deal with this is (my instinct would be for the cell vectors to just be ignored) - might be best to be consistent with what ASE thinks should happen. But it'd be nice if this was detected at least.