I think it's more natural to say "at" the corner here, and use "on the corner" when referring to a road (which must be specified either implicitly or explicitly), e.g. "on the corner of Main Street"
That might be what they meant anyway, but it's worth mentioning
I think the thing is that Hungarian does not make this distinction. But Hungarian also uses the "at" kind of suffix. For example, "driver, please stop at the corner", or "turn right at the corner", these woule be said with "saroknál".
I live in California and here 'at' the corner sounds weird to me. 'On' the corner is way more natural.
Unless you describe something after 'the corner'. For example. Three girls stand at the corner of Main and Third. But, three girls stand on the corner.
Is this word also used for the corner of a room? How would you say "in the corner"?