when I have a villager so near and hours later they still so near , I either
a, give them a new skill for 10 minutes, eg healing make them learn the shrubs , put them back on building and wow they are master , that may be a coincidence, but maybe they need new stimuli to learn ,

or B, this has been said... switch game off for a bit , bit meaning an hour and you may come back to a celebration!!

as the old adage says, a watched pot never boils!! of course that is scientifically nonsense but its psychologically probable