This. This stuff happens all the time. So there is a new construction planned somewhere, workers accidentally find some walls etc. Archeological team is dispatched, they remove much more ground, as much as to see how big the object(s) are, what era, figure out they have a archeological gold mine. But they don't have resources (money) allocated for it yet, so they will rebury it. Next year, or in the coming years they'll come back and do the proper excavation. And if I may add a bit sarcastically, a PhD or three.
> In some cases, resources (like money, staff and proper materials) are not available to properly maintain the site.