Along with what others said about it getting your highest, I can imagine exploits by trading a settlement back and forth if the counter cannot decreaseI think legacy path milestones should stay completed once achieved. It's really painful for the exploration age military legacy path when AIs constantly convert some of your distant land settlements and you loose 2 points for that.
Or is this just a UI thing and it counts as completed once you did it, despite the bar indicating something different?
