When you click on or near the allotment, it retrieves the allotment and hence the multipolygon.

When you click outside the allotment, it does not detect any member of the multipolygon and therefore does not show it. Multipolygons are treated differently than plain areas. I can only assume that nominatim's query feature simply does not check for multipolygons which contain the queried coordinate.

(On higher zoom levels, it will start working again, since the outer way(s) of the multipolygon are covered by the search query.)