In frontend Configuration > Action > Operations there is a limit to fields 'From' ('esc_step_from') and 'To' ('esc_step_to') beeing limited to 5 symbols.
However in API those fields don't validate properly and there is no maximum value. User can enter an integer 999999999, for example.
Creating such action with large numbers in those fields and opening it in frontend will show blank page with only header.
It would also be good to validate field 'Step duration' ('esc_period') to prevent entering values larger than frontend.