that’s not 100% required so I doubt it would cause it to not work. It will just print an error in the log that it couldn’t find a valid service call when the template is evaluated.
Sure but there really is no need for a template that works but generates errors sometimes when instead a simple condition can handle the logic required without ever causing errors.
You should have received an error for group or any other entity. You had no action: block in your automation and the service template is not indented correctly. Maybe you accidentally deleted that when editing the entity?
FYI this is what it should have looked like:
- id: front_lights_a
alias: Front Lights A
trigger:
- at: '00:00'
platform: time
condition: []
action:
- service_template: >
{% if is_state('group.front_lights_group', 'on') %}
script.front_lights_s
{% endif %}
Though as pointed out above, because there is no else statement this will generate errors when the template evaluates as false (no entity id will be specified for the service call).