The Greek adverbial expression rendered around is the same one translated back in 18.6.

And saw Jesus standing there is literally “and saw Jesus standing” (so Revised Standard Version). To translate without the adverb there in English would focus the reader’s attention on standing as opposed to sitting, rather than on the fact that Jesus was at that particular place, which is the point in focus here. Jerusalem Bible, New English Bible, New American Bible, and others include the adverb there for the same reason. In some languages the statement she … saw Jesus standing there seems inconsistent with what follows, namely, she did not know that it was Jesus. Since a literal translation of she … saw Jesus standing there might imply that she recognized who he was, it may be better to render the second part of this verse “she saw a man standing there; it was Jesus, but she did not know that it was Jesus” or “… did not recognize him as Jesus.”

But she did not know that it was Jesus (so Revised Standard Version, New English Bible “but did not recognize him”; New American Bible “But she did not know him”; Jerusalem Bible “though she did not recognize him”) represents a literal rendering of the Greek text. John does not suggest why Mary did not recognize Jesus.

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .