I have encountered a problem with EvolutionStrategy: it does not work with constraints. However, the problem seems to be fixed by changing this line in the implementation of EvolutionStrategy:
population_pool.sort(key=lambda s: (overall_constraint_violation_degree(s), s.objectives[0]))
to:
population_pool.sort(key=lambda s: (-overall_constraint_violation_degree(s), s.objectives[0]))
(adding a minus sign before overall_constraint_violation_degree, as it is a sum of negative numbers).