I think that responsibility is up to the course moderators, since they are the ones who check and confirm the incoming reports. But I can't really blame them either, since not everyone is aware of that "automatic expansion" thing and "It's not cloudy" is indeed a proper translation.
Piotr, those are two very different words. Esta (without accent) is the feminine form of este, and it's a demonstrative that means "this": "esta silla" - "this chair".
Está (with an accent on the 'a'; please note that all accents in Spanish go upwards) is a conjugated form of the verb estar. It's the present-tense él/ella form and translates as "he/she/it is".
- no está nublado - it is not cloudy
- esta mañana - this morning