It works for me so you must have done something wrong.
Your previous message quoted the Template Condition I posted and then proceeded to discuss a completely different Template Condition. Was there a question and was it meant for me?
An entity_id is a slug (meaning a string that has no whitespace or non-ASCII characters and is in lower-case). Given that format, I don’t see how the group’s entity_id could contain upper-case letters.
@Marcweemer
The entity’s entity_id is shown in Developer Tools > States and that’s what should be used when referencing it in templates, scripts, automations, etc.