reloading world causes 'unofficialisation' of buildings

[imnotanexpert]

in my player controlled custom-townhall village, for some reason, quitting minecraft and reloading the world, causes the other buildings to remove themselves from the village map and become yellow (as in player placed blocks). the inhabitants continue to use and live in the buildings and still appear on the map and villagers list however.

edit: although this might just be when my computer suddenly shuts down (instant).