They did though. While nobody actually believed Putin would be dumb enough, the Ukrainian army was still, just in case, extremely busy on preparing defences, organising stockpiles, preparing defensive tactics.
I'm not sure why you'd say nobody thought they would invade. To me it was clear in December the year before when the Russian navy began sailing the long way around Europe, getting in the way of Irish fisherman and confirmed days before the invasion when they had stockpiled medical personnel and blood on the front lines.
https://en.wikipedia.org/wiki/Novorossiya_(confederation)
But it seems Ukraine had questionable control of the eastern parts of the country long before the 2022 "official" invasion.
There was at least one other buildup of around 100k troops in the intervening years, but I don't think they moved their naval assets from the north or bring blood supply to the front.
It seemed to me like they went quiet for most of the 8 years, I'd be curious what you may have seen that made it more clear based mainly on the 2014 invasion(s).