I did the focus "King" of Aquileia, got the event where Vivienne got couped by the Strawberry General, and took over the country.

I can't do the rest of the Aquileia tree because of the coup firing and waited to see if anything else happened, but nothing.

Obviously it's possible for a coup to not happen, but I have no idea how to avoid it besides taking the focus path that doesn't say a coup is very likely. Is it pure RNG?

Also, the event from Aquileia's perspective (tag-switched when they got the event "King"), and it says Vivienne escaped to Arantiga. Does this mean I just have to wait for something with her to happen?