What's different about yours, that might not necessarily merit explicit mention all the time but which other characters may well notice/have heard?
Polly now wears her hair in a braid. This does not, technically, have anything to do with Duo; she wears her hair long as a political statement, but is aware that this could be a danger in combat, so she keeps it well back for practical reasons. Nevertheless, it's likely to get her a few odd looks from people who know about him.
She is also much, much harder. Partly this is because of her loss, which she's dealt with by trying to lose herself in her task. It is also, in large part, because of the spot of bother with Zlobenia shortly after her return. Objectively, it could easily have been so much worse- Blouse's genius with military semaphore, Polly's gift for manipulation, and most people's instinctive reluctance to harm known women helped keep the body count low- but it was still an unforgettable event, including the deaths of a few comrades-in-arms and Polly's own first (plus a couple more, but of course the first is the biggest deal) kill.
To her, the Island now represents self-indulgence. She got respect and could do things for herself, because her hardest duty was unavailable for performing. If she got the chance to return permanently? It'd kill her, but I don't think she would.