It seems to to me. Item 9, "Use \mathbb or \Bbb for 'blackboard bold'"

Yes, but typing somewhere else shows double lined (only for capital) alphabets instead of what's in the meta

@UmbQbify-Key20- Yes, it should be double-lined. Can you give a screenshot of what you are seeing on the meta page? (I'm not sure this is the correct place for this though. You'd be better asking in meta.)

Alright

Looks it was a processing delay. Took the browser 3+ minutes to load everything perfectly. mathbb happened to be the last of it