"Вчора ми були у офісі."

Translation: Yesterday we were in the office.

[MatteoDima19]

We were in the office yesterday should also be accepted.

[katszwedo]

Why is it 'у офісі' instead of 'в офісі'? Shouldn't it follow the rule 'в between 2 vowels'?

[GeneM.]

From what I understand, Duo is inconsistent with this rule. Also, Ukrainians (as mentioned in Tips & Notes) don't always follow this rule. They can break the rules just like native speakers of other languages.

[BohdanaKaz]

В офісі