It wasn't shown, but it implied at the beginning of chapter 68 that they have resolved the issue with the south... Maybe it wasn't shown since it wasn't something that Lyrica had much involvement in since everything is being handled independently in the background by her parents since we're all seeing everything in Lyrica's POV. I would like to imagine that during that timeskip, Lyrica had focused on healing after the poison event which could have been majorly traumatizing for her.

the scene change from the poison incident to her bday (c67 to c68) is too sudden. we almost had no conclusion for the poison incident, the empress was planning something but wasnt shown at all, then suddenly it jumped to her bday? and iirc she was 8 at the beginning so it mustve been a timeskip (also explains why bryn's hair is much longer now) but the way it was executed made no sense, it feels like we're missing a chapter in between ngl